by Keyword: Article

Bonany M, Pérez-Berná AJ, Dučić T, Pereiro E, Martin-Gómez H, Mas-Moruno C, van Rijt S, Zhao Z, Espanol M, Ginebra MP, (2022). Hydroxyapatite nanoparticles-cell interaction: New approaches to disclose the fate of membrane-bound and internalised nanoparticles Biomaterials Advances 142, 213148

Hydroxyapatite nanoparticles are popular tools in bone regeneration, but they have also been used for gene delivery and as anticancer drugs. Understanding their mechanism of action, particularly for the latter application, is crucial to predict their toxicity. To this end, we aimed to elucidate the importance of nanoparticle membrane interactions in the cytotoxicity of MG-63 cells using two different types of nanoparticles. In addition, conventional techniques for studying nanoparticle internalisation were evaluated and compared with newer and less exploited approaches. Hydroxyapatite and magnesium-doped hydroxyapatite nanoparticles were used as suspensions or compacted as specular discs. Comparison between cells seeded on the discs and those supplemented with the nanoparticles allowed direct interaction of the cell membrane with the material to be ruled out as the main mechanism of toxicity. In addition, standard techniques such as flow cytometry were inconclusive when used to assess nanoparticles toxicity. Interestingly, the use of intracellular calcium fluorescent probes revealed the presence of a high number of calcium-rich vesicles after nanoparticle supplementation in cell culture. These structures could not be detected by transmission electron microscopy due to their liquid content. However, by using cryo-soft X-ray imaging, which was used to visualise the cellular ultrastructure without further treatment other than vitrification and to quantify the linear absorption coefficient of each organelle, it was possible to identify them as multivesicular bodies, potentially acting as calcium stores. In the study, an advanced state of degradation of the hydroxyapatite and magnesium-doped hydroxyapatite nanoparticles within MG-63 cells was observed. Overall, we demonstrate that the combination of fluorescent calcium probes together with cryo-SXT is an excellent approach to investigate intracellular calcium, especially when found in its soluble form.Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.

JTD Keywords: adsorption, cryo-soft x-ray tomography, cytotoxicity, expression, flow cytometry, internalisation, intracellular calcium, magnesium, nano, nanomaterials, nanoparticles, proliferation, protein corona, ultrastructure, Calcium-phosphate nanoparticles, Cryo-soft x-ray tomography, Flow cytometry, Hydroxyapatite, Internalisation, Intracellular calcium, Nanoparticles

Pala, M, El Khannaji, H, Garay-Sarmiento, M, Ronda, JC, Cadiz, V, Galia, M, Percec, V, Rodriguez-Emmenegger, C, Lligadas, G, (2022). A green solvent-to-polymer upgrading approach to water-soluble LCST poly(N-substituted lactamide acrylate)s Green Chemistry 21, 8314-8323

We report a green solvent-to-polymer upgrading transformation of chemicals of the lactic acid portfolio into water-soluble lower critical solution temperature (LCST)-type acrylic polymers. Aqueous Cu(0)-mediated living radical polymerization (SET-LRP) was utilized for the rapid synthesis of N-substituted lactamide-type homo and random acrylic copolymers under mild conditions. A particularly unique aspect of this work is that the water-soluble monomers and the SET-LRP initiator used to produce the corresponding polymers were synthesized from biorenewable and non-toxic solvents, namely natural ethyl lactate and BASF's Agnique (R) AMD 3L (N,N-dimethyl lactamide, DML). The pre-disproportionation of Cu(I) Br in the presence of tris[2-(dimethylamino)ethyl]amine (Me6TREN) in water generated nascent Cu(0) and Cu(II) complexes that facilitated the fast polymerization of N-tetrahydrofurfuryl lactamide and N,N-dimethyl lactamide acrylate monomers (THFLA and DMLA, respectively) up to near-quantitative conversion with excellent control over molecular weight (5000 < M-n < 83 000) and dispersity (1.05 < D < 1.16). Interestingly, poly(THFLA) showed a degree of polymerization and concentration dependent LCST behavior, which can be fine-tuned (T-cp = 12-62 degrees C) through random copolymerization with the more hydrophilic DMLA monomer. Finally, covalent cross-linking of these polymers resulted in a new family of thermo-responsive hydrogels with excellent biocompatibility and tunable swelling and LCST transition. These illustrate the versatility of these neoteric green polymers in the preparation of smart and biocompatible soft materials.

JTD Keywords: Acid, Ethyl lactate, Living radical polymerization, Monomers, Pnipam, Reductive amination, Ruthenium nanoparticles, Set-lrp, Single, Thermoresponsive polymers

De Lama-Odría, María del Carmen, del Valle, Luis J., Puiggalí, Jordi, (2022). Hydroxyapatite Biobased Materials for Treatment and Diagnosis of Cancer International Journal Of Molecular Sciences 23, 11352

Great advances in cancer treatment have been undertaken in the last years as a consequence of the development of new antitumoral drugs able to target cancer cells with decreasing side effects and a better understanding of the behavior of neoplastic cells during invasion and metastasis. Specifically, drug delivery systems (DDS) based on the use of hydroxyapatite nanoparticles (HAp NPs) are gaining attention and merit a comprehensive review focused on their potential applications. These are derived from the intrinsic properties of HAp (e.g., biocompatibility and biodegradability), together with the easy functionalization and easy control of porosity, crystallinity and morphology of HAp NPs. The capacity to tailor the properties of DLS based on HAp NPs has well-recognized advantages for the control of both drug loading and release. Furthermore, the functionalization of NPs allows a targeted uptake in tumoral cells while their rapid elimination by the reticuloendothelial system (RES) can be avoided. Advances in HAp NPs involve not only their use as drug nanocarriers but also their employment as nanosystems for magnetic hyperthermia therapy, gene delivery systems, adjuvants for cancer immunotherapy and nanoparticles for cell imaging.

JTD Keywords: antitumoral, cell imaging, controlled-release, drug-carrier, efficient drug-delivery, fatty-acid-metabolism, fe3o4 nanoparticles, gene delivery, hydroxyapatite, hyperthermia, immunotherapy, in-vitro, magnetic hydroxyapatite, nano-hydroxyapatite, protein adsorption, tumor-growth, Calcium-phosphate nanoparticles, Cancer

Hodásová, Ľudmila, Morena, AGala, Tzanov, Tzanko, Fargas, Gemma, Llanes, Luis, Alemán, Carlos, Armelin, Elaine, (2022). 3D-Printed Polymer-Infiltrated Ceramic Network with Antibacterial Biobased Silver Nanoparticles Acs Applied Bio Materials 5, 4803-4813

Wang, Yuyang, Soto Rodriguez, Paul ED., Woythe, Laura, Sánchez, Samuel, Samitier, Josep, Zijlstra, Peter, Albertazzi, Lorenzo, (2022). Multicolor Super-Resolution Microscopy of Protein Corona on Single Nanoparticles Acs Applied Materials & Interfaces 14, 37345-37355

Battaglini M, Feiner N, Tapeinos C, De Pasquale D, Pucci C, Marino A, Bartolucci M, Petretto A, Albertazzi L, Ciofani G, (2022). Combining confocal microscopy, dSTORM, and mass spectroscopy to unveil the evolution of the protein corona associated with nanostructured lipid carriers during blood-brain barrier crossing Nanoscale 14, 13292-13307

Upon coming into contact with the biological environment, nanostructures are immediately covered by biomolecules, particularly by proteins forming the so-called "protein corona" (PC). The phenomenon of PC formation has gained great attention in recent years due to its implication in the use of nanostructures in biomedicine. In fact, it has been shown that the formation of the PC can impact the performance of nanostructures by reducing their stability, causing aggregation, increasing their toxicity, and providing unexpected and undesired nanostructure-cell interactions. In this work, we decided to study for the first time the formation and the evolution of PC on the surface of nanostructured lipid carriers loaded with superparamagnetic iron oxide nanoparticles, before and after the crossing of an in vitro model of the blood-brain barrier (BBB). Combining confocal microscopy, direct STochastic Optical Reconstruction Microscopy (dSTORM), and proteomic analysis, we were able to carry out a complete analysis of the PC formation and evolution. In particular, we highlighted that PC formation is a fast process, being formed around particles even after just 1 min of exposure to fetal bovine serum. Moreover, PC formed around particles is extremely heterogeneous: while some particles have no associated PC at all, others are completely covered by proteins. Lastly, the interaction with an in vitro BBB model strongly affects the PC composition: in particular, a large amount of the proteins forming the initial PC is lost after the BBB passage and they are partially replaced by new proteins derived from both the brain endothelial cells and the cell culture medium. Altogether, the obtained data could potentially provide new insights into the design and fabrication of lipid nanostructures for the treatment of central nervous system disorders.

JTD Keywords: design, impact, Nanoparticles

F Amil A, Rubio Ballester B, Maier M, FMJ Verschure P, (2022). Chronic use of cannabis might impair sensory error processing in the cerebellum through endocannabinoid dysregulation Addictive Behaviors 131, 107297

Chronic use of cannabis leads to both motor deficits and the downregulation of CB1 receptors (CB1R) in the cerebellum. In turn, cerebellar damage is often related to impairments in motor learning and control. Further, a recent motor learning task that measures cerebellar-dependent adaptation has been shown to distinguish well between healthy subjects and chronic cannabis users. Thus, the deteriorating effects of chronic cannabis use in motor performance point to cerebellar adaptation as a key process to explain such deficits. We review the literature relating chronic cannabis use, the endocannabinoid system in the cerebellum, and different forms of cerebellar-dependent motor learning, to suggest that CB1R downregulation leads to a generalized underestimation and misprocessing of the sensory errors driving synaptic updates in the cerebellar cortex. Further, we test our hypothesis with a computational model performing a motor adaptation task and reproduce the behavioral effect of decreased implicit adaptation that appears to be a sign of chronic cannabis use. Finally, we discuss the potential of our hypothesis to explain similar phenomena related to motor impairments following chronic alcohol dependency. © 2022

JTD Keywords: adaptation, addiction, alcohol-abuse, cerebellum, cognition, deficits, endocannabinoid system, error processing, explicit, modulation, motor learning, release, synaptic plasticity, Adaptation, Adaptation, physiological, Alcoholism, Article, Behavioral science, Cannabinoid 1 receptor, Cannabis, Cannabis addiction, Cerebellum, Cerebellum cortex, Cerebellum disease, Chronic cannabis use, Computer model, Down regulation, Endocannabinoid, Endocannabinoid system, Endocannabinoids, Error processing, Hallucinogens, Human, Humans, Motor dysfunction, Motor learning, Nerve cell plasticity, Nonhuman, Physiology, Psychedelic agent, Purkinje-cells, Regulatory mechanism, Sensation, Sensory dysfunction, Sensory error processing impairment, Synaptic transmission, Task performance

Roki, Nikša, Solomon, Melani, Bowers, Jessica, Getts, Lori, Getts, Robert C., Muro, Silvia, (2022). Tuning Design Parameters of ICAM-1-Targeted 3DNA Nanocarriers to Optimize Pulmonary Targeting Depending on Drug Type Pharmaceutics 14, 1496

3DNA holds promise as a carrier for drugs that can be intercalated into its core or linked to surface arms. Coupling 3DNA to an antibody targeting intercellular adhesion molecule 1 (ICAM-1) results in high lung-specific biodistributions in vivo. While the role of individual parameters on ICAM-1 targeting has been studied for other nanocarriers, it has never been examined for 3DNA or in a manner capable of revealing the hierarchic interplay among said parameters. In this study, we used 2-layer vs. 4-layer anti-ICAM 3DNA and radiotracing to examine biodistribution in mice. We found that, below saturating conditions and within the ranges tested, the density of targeting antibodies on 3DNA is the most relevant parameter driving lung targeting over liver clearance, compared to the number of antibodies per carrier, total antibody dose, 3DNA dose, 3DNA size, or the administered concentration, which influenced the dose in organs but not the lung specific-over-liver clearance ratio. Data predicts that lung-specific delivery of intercalating (core loaded) drugs can be tuned using this biodistribution pattern, while that of arm-linked (surface loaded) drugs requires a careful parametric balance because increasing anti-ICAM density reduces the number of 3DNA arms available for drug loading.

JTD Keywords: acid sphingomyelinase, antibody, carrier design parameters, carriers, dna nanostructures, doxorubicin, drug type, icam-1, inflammation, lung targeting, multiparametric hierarchy, nanoparticles, size, 3dna nanocarrier, Intracellular delivery

Morla-Folch, J, Vargas-Nadal, G, Fuentes, E, Illa-Tuset, S, Koeber, M, Sissa, C, Pujals, S, Painelli, A, Veciana, J, Faraudo, J, Belfield, KD, Albertazzi, L, Ventosa, N, (2022). Ultrabright Foster Resonance Energy Transfer Nanovesicles: The Role of Dye Diffusion Chemistry Of Materials 34, 8517-8527

The development of contrast agents based on fluorescent nanoparticles with high brightness and stability is a key factor to improve the resolution and signal-to-noise ratio of current fluorescence imaging techniques. However, the design of bright fluorescent nanoparticles remains challenging due to fluorescence self-quenching at high concentrations. Developing bright nanoparticles showing FRET emission adds several advantages to the system, including an amplified Stokes shift, the possibility of ratiometric measurements, and of verifying the nanoparticle stability. Herein, we have developed Forster resonance energy transfer (FRET)-based nanovesicles at different dye loadings and investigated them through complementary experimental techniques, including conventional fluorescence spectroscopy and super-resolution microscopy supported by molecular dynamics calculations. We show that the optical properties can be modulated by dye loading at the nanoscopic level due to the dye's molecular diffusion in fluid-like membranes. This work shows the first proof of a FRET pair dye's dynamism in liquid-like membranes, resulting in optimized nanoprobes that are 120-fold brighter than QDot 605 and exhibit >80% FRET efficiency with vesicle-to-vesicle variations that are mostly below 10%.

JTD Keywords: Bright, Dendrimers, Fluorescent, In-vivo, Nanoparticles, Nir, Particles

Rizzello, L, De Matteis, V, (2022). Identification of SARS-CoV-2 by Gold Nanoparticles Biocell 46, 2369-2380

The SARS-CoV-2 outbreaks highlighted the need for effective, reliable, fast, easy-to-do and cheap diagnostics procedures. We pragmatically experienced that an early positive-case detection, inevitably coupled with a mass vaccination campaign, is a milestone to control the COVID-19 pandemic. Gold nanoparticles (AuNPs) can indeed play a crucial role in this context, as their physicochemical, optics and electronics properties are being extensively used in photothermal therapy (PTT), radiation therapy (RT), drug delivery and diagnostic. AuNPs can be synthesized by several approaches to obtain different sizes and shapes that can be easily functionalized with many kinds of molecules such as antibodies, proteins, probes, and lipids. In addition, AuNPs showed high biocompatibility making them useful tool in medicine field. We thus reviewed here the most relevant evidence on AuNPs as effective way to detect the presence of SARS-CoV-2 antigens. We trust future diagnostic efforts must take this 'old-fashioned' nanotechnology tool into consideration for the development and commercialization of reliable and feasible detection kits.

JTD Keywords: Aggregation, Antibodies, Assay, Covid-19, Diagnosis, Enhanced raman-scattering, Gold nanoparticles, Immunoassay, Pandemic disease, Physicochemical properties, Rapid detection, Sars-cov-2, Sensors, Surface-plasmon resonance, Therapy

Riera, Roger, Tauler, Jana, Feiner Gracia, Natàlia, Borrós, Salvador, Fornaguera, Cristina, Albertazzi, Lorenzo, (2022). Complex pBAE Nanoparticle Cell Trafficking: Tracking Both Position and Composition Using Super Resolution Microscopy Chemmedchem 17, e202100633

Nanomedicine emerged some decades ago with the hope to be the solution for most unmet medical needs. However, tracking materials at nanoscale is challenging to their reduced size, below the resolution limit of most conventional techniques. In this context, we propose the use of direct stochastic optical reconstruction microscopy (dSTORM) to study time stability and cell trafficking after transfection of oligopeptide end-modified poly(?-aminoester) (OM-pBAE) nanoparticles. We selected different combinations of cationic end oligopeptides (arginine - R; histidine - H; and lysine - K) among polymer libraries, since the oligopeptide combination demonstrated to be useful for different applications, such as vaccination and gene silencing. We demonstrate that their time evolution as well as their cell uptake and trafficking are dependent on the oligopeptide. This study opens the pave to broad mechanistic studies at nanoscale that could enable a rational selection of specific pBAE nanoparticles composition after determining their stability and cell trafficking.© 2022 The Authors. ChemMedChem published by Wiley-VCH GmbH.

JTD Keywords: cancer nanomedicine, cell trafficking, delivery, direct stochastic optical reconstruction microscopy (dstorm), nanoparticle stability, poly(beta-aminoester) nanoparticles, Direct stochastic optical reconstruction microscopy (dstorm), Poly(?-aminoester) nanoparticles, Poly(beta-amino ester)s

Chattopadhyay, P, Magdanz, V, Hernandez-Melia, M, Borchert, KBL, Schwarz, D, Simmchen, J, (2022). Size-Dependent Inhibition of Sperm Motility by Copper Particles as a Path toward Male Contraception Advanced Nanobiomed Research 2, 2100152

Effective inhibition of sperm motility using a spermicide can be a promising approach in developing non-invasive male contraceptive agents. Copper is known to have contraceptive properties and has been used clinically for decades as intrauterine contraceptive devices (IUDs) for contraception in females. Beyond that, the spermicidal use of copper is not explored much further, even though its use can also subdue the harmful effects caused by the hormonal female contraceptive agents on the environment. Herein, the size, concentration, and time-dependent in vitro inhibition of bovine spermatozoa by copper microparticles are studied. The effectivity in inhibiting sperm motility is correlated with the amount of Cu2+ ions released by the particles during incubation. The copper particles cause direct suppression of sperm motility and viability upon incubation and thereby show potential as sperm-inhibiting, hormone-free candidate for male contraception. In addition, biocompatibility tests using a cervical cell line help optimizing the size and concentration of the copper particles for the best spermicidal action while avoiding toxicity to the surrounding tissue.

JTD Keywords: Bovine spermatozoa, Clinical-trial, Copper, Human-spermatozoa, Ions, Male contraception, Metallic copper, Microparticles, Progestins, Sperm motility, Sperm viability, Spermicide, Viability

Sans, Jordi, Arnau, Marc, Turon, Pau, Alemán, Carlos, (2022). Permanently polarized hydroxyapatite, an outstanding catalytic material for carbon and nitrogen fixation Materials Horizons 9, 1566-1576

Permanently polarized hydroxyapatite is a new material with electrical enhanced properties. This review discusses the advances in this material in terms of structure, properties and catalytic activity of green processes.

JTD Keywords: ammonia, bone, copper hydroxyapatite, electrophotosynthesis, nanoparticles, oxidation, phase-transition, reduction, Amino-acids

Lanzalaco, Sonia, Gil, Pau, Mingot, Júlia, Àgueda, Alba, Alemán, Carlos, Armelin, Elaine, (2022). Dual-Responsive Polypropylene Meshes Actuating as Thermal and SERS Sensors Acs Biomaterials Science & Engineering 8, 3329-3340

Arque, X, Torres, MDT, Patino, T, Boaro, A, Sanchez, S, de la Fuente-Nunez, C, (2022). Autonomous Treatment of Bacterial Infections in Vivo Using Antimicrobial Micro- and Nanomotors Acs Nano 16, 7547-7558

The increasing resistance of bacteria to existing antibiotics constitutes a major public health threat globally. Most current antibiotic treatments are hindered by poor delivery to the infection site, leading to undesired off-target effects and drug resistance development and spread. Here, we describe micro- and nanomotors that effectively and autonomously deliver antibiotic payloads to the target area. The active motion and antimicrobial activity of the silica-based robots are driven by catalysis of the enzyme urease and antimicrobial peptides, respectively. These antimicrobial motors show micromolar bactericidal activity in vitro against different Gram-positive and Gram-negative pathogenic bacterial strains and act by rapidly depolarizing their membrane. Finally, they demonstrated autonomous anti-infective efficacy in vivo in a clinically relevant abscess infection mouse model. In summary, our motors combine navigation, catalytic conversion, and bactericidal capacity to deliver antimicrobial payloads to specific infection sites. This technology represents a much-needed tool to direct therapeutics to their target to help combat drug-resistant infections.

JTD Keywords: antibiotic-resistance, antimicrobial peptides, autonomous treatment, bacterial infection, delivery, ll-37, nanoparticles, peptide, self-propulsion, tissue, vitro, wasp venom, Antibiotic-resistance, Antimicrobial peptides, Autonomous treatment, Bacterial infection, Delivery, Ll-37, Mesoporous silica nanoparticles, Nanomotors, Nanoparticles, Peptide, Self-propulsion, Tissue, Vitro, Wasp venom

Martí D, Martín-Martínez E, Torras J, Betran O, Turon P, Alemán C, (2022). In silico study of substrate chemistry effect on the tethering of engineered antibodies for SARS-CoV-2 detection: Amorphous silica vs gold Colloids And Surfaces B-Biointerfaces 213, 112400

The influence of the properties of different solid substrates on the tethering of two antibodies, IgG1-CR3022 and IgG1-S309, which were specifically engineered for the detection of SARS-CoV-2, has been examined at the molecular level using conventional and accelerated Molecular Dynamics (cMD and aMD, respectively). Two surfaces with very different properties and widely used in immunosensors for diagnosis, amorphous silica and the most stable facet of the face-centered cubic gold structure, have been considered. The effects of such surfaces on the structure and orientation of the immobilized antibodies have been determined by quantifying the tilt and hinge angles that describe the orientation and shape of the antibody, respectively, and the dihedrals that measure the relative position of the antibody arms with respect to the surface. Results show that the interactions with amorphous silica, which are mainly electrostatic due to the charged nature of the surface, help to preserve the orientation and structure of the antibodies, especially of the IgG1-CR3022, indicating that the primary sequence of those antibodies also plays some role. Instead, short-range van der Waals interactions with the inert gold surface cause a higher degree tilting and fraying of the antibodies with respect to amorphous silica. The interactions between the antibodies and the surface also affect the correlation among the different angles and dihedrals, which increases with their strength. Overall, results explain why amorphous silica substrates are frequently used to immobilize antibodies in immunosensors. © 2022 The Authors

JTD Keywords: amorphous silica, enzyme, gol d, immobilization, immunosensor, molecu l a r dynamics, protein adsorption, sars-cov-2 immunosensor, simulations, spike protein, surface interactions, target, vaccine, Amorphous silica, Antibodies, Antibody engineering, Antibody immobilization, Antibody structure, Article, Chemical detection, Computer model, Controlled study, Dihedral angle, Gold, In-silico, Molecular dynamics, Molecular levels, Molecular-dynamics, Nonhuman, Property, Sars, Sars-cov-2 immunosensor, Severe acute respiratory syndrome coronavirus 2, Silica, Silico studies, Silicon dioxide, Solid substrates, Structure analysis, Substrate chemistry, Substrates, Van der waals forces, Virus detection

Muntimadugu, Eameema, Silva-Abreu, Marcelle, Vives, Guillem, Loeck, Maximilian, Pham, Vy, del Moral, Maria, Solomon, Melani, Muro, Silvia, (2022). Comparison between Nanoparticle Encapsulation and Surface Loading for Lysosomal Enzyme Replacement Therapy International Journal Of Molecular Sciences 23, 4034

Poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) enhance the delivery of therapeutic enzymes for replacement therapy of lysosomal storage disorders. Previous studies examined NPs encapsulating or coated with enzymes, but these formulations have never been compared. We examined this using hyaluronidase (HAse), deficient in mucopolysaccharidosis IX, and acid sphingomyelinase (ASM), deficient in types A–B Niemann–Pick disease. Initial screening of size, PDI, ζ potential, and loading resulted in the selection of the Lactel II co-polymer vs. Lactel I or Resomer, and Pluronic F68 surfactant vs. PVA or DMAB. Enzyme input and addition of carrier protein were evaluated, rendering NPs having, e.g., 181 nm diameter, 0.15 PDI, −36 mV ζ potential, and 538 HAse molecules encapsulated per NP. Similar NPs were coated with enzyme, which reduced loading (e.g., 292 HAse molecules/NP). NPs were coated with targeting antibodies (> 122 molecules/NP), lyophilized for storage without alterations, and acceptably stable at physiological conditions. NPs were internalized, trafficked to lysosomes, released active enzyme at lysosomal conditions, and targeted both peripheral organs and the brain after i.v. administration in mice. While both formulations enhanced enzyme delivery compared to free enzyme, encapsulating NPs surpassed coated counterparts (18.4- vs. 4.3-fold enhancement in cells and 6.2- vs. 3-fold enhancement in brains), providing guidance for future applications.

JTD Keywords: active enzymes, encapsulation, enhanced delivery, formulation parameters, icam-1 targeting, icam-1-targeted nanocarriers, in vivo biodistribution, in-vitro, lysosomal delivery, model, oral delivery, plga nanoparticles, poly(lactic-co-glycolic acid) nanoparticles, protein therapeutics, surface loading, Acid sphingomyelinase, Enzyme therapeutics

Ballester BR, Winstein C, Schweighofer N, (2022). Virtuous and Vicious Cycles of Arm Use and Function Post-stroke Frontiers In Neurology 13,

Large doses of movement practice have been shown to restore upper extremities' motor function in a significant subset of individuals post-stroke. However, such large doses are both difficult to implement in the clinic and highly inefficient. In addition, an important reduction in upper extremity function and use is commonly seen following rehabilitation-induced gains, resulting in “rehabilitation in vain”. For those with mild to moderate sensorimotor impairment, the limited spontaneous use of the more affected limb during activities of daily living has been previously proposed to cause a decline of motor function, initiating a vicious cycle of recovery, in which non-use and poor performance reinforce each other. Here, we review computational, experimental, and clinical studies that support the view that if arm use is raised above an effective threshold, one enters a virtuous cycle in which arm use and function can reinforce each other via self-practice in the wild. If not, one enters a vicious cycle of declining arm use and function. In turn, and in line with best practice therapy recommendations, this virtuous/vicious cycle model advocates for a paradigm shift in neurorehabilitation whereby rehabilitation be embedded in activities of daily living such that self-practice with the aid of wearable technology that reminds and motivates can enhance paretic limb use of those who possess adequate residual sensorimotor capacity. Altogether, this model points to a user-centered approach to recovery post-stroke that is tailored to the participant's level of arm use and designed to motivate and engage in self-practice through progressive success in accomplishing meaningful activities in the wild. Copyright © 2022 Ballester, Winstein and Schweighofer.

JTD Keywords: Arm movement, Article, Cerebrovascular accident, Clinical decision making, Clinical practice, Clinical study, Compensatory movement, Computational neurorehabilitation, Computer model, Daily life activity, Decision-making, Experimental study, Human, Learned non-use, Musculoskeletal function, Neurorehabilitation, Paresis, Sensorimotor function, Stroke, Stroke rehabilitation, User-centered design, Vicious cycle, Virtuous cycle, Wearable sensors

Valles, Morgane, Pujals, Sílvia, Albertazzi, Lorenzo, Sánchez, Samuel, (2022). Enzyme Purification Improves the Enzyme Loading, Self-Propulsion, and Endurance Performance of Micromotors Acs Nano 16, 5615-5626

Woythe L, Madhikar P, Feiner-Gracia N, Storm C, Albertazzi L, (2022). A Single-Molecule View at Nanoparticle Targeting Selectivity: Correlating Ligand Functionality and Cell Receptor Density Acs Nano 16, 3785-3796

Antibody-functionalized nanoparticles (NPs) are commonly used to increase the targeting selectivity toward cells of interest. At a molecular level, the number of functional antibodies on the NP surface and the density of receptors on the target cell determine the targeting interaction. To rationally develop selective NPs, the single-molecule quantitation of both parameters is highly desirable. However, techniques able to count molecules with a nanometric resolution are scarce. Here, we developed a labeling approach to quantify the number of functional cetuximabs conjugated to NPs and the expression of epidermal growth factor receptors (EGFRs) in breast cancer cells using direct stochastic optical reconstruction microscopy (dSTORM). The single-molecule resolution of dSTORM allows quantifying molecules at the nanoscale, giving a detailed insight into the distributions of individual NP ligands and cell receptors. Additionally, we predicted the fraction of accessible antibody-conjugated NPs using a geometrical model, showing that the total number exceeds the accessible number of antibodies. Finally, we correlated the NP functionality, cell receptor density, and NP uptake to identify the highest cell uptake selectivity regimes. We conclude that single-molecule functionality mapping using dSTORM provides a molecular understanding of NP targeting, aiding the rational design of selective nanomedicines.

JTD Keywords: active targeting, active targeting dstorm, antibodies, dstorm, heterogeneity, multivalency, nanomedicine, nanoparticle functionality, size, super-resolution microscopy, surface, Active targeting, Antibodies, Cell membranes, Cell receptors, Cytology, Direct stochastic optical reconstruction microscopy, Dstorm, Heterogeneity, Ligands, Medical nanotechnology, Molecules, Nanomedicine, Nanoparticle functionality, Nanoparticle targeting, Nanoparticles, Optical reconstruction, Single molecule, Stochastic systems, Stochastics, Super-resolution microscopy, Superresolution microscopy

Bonilla-Pons SÀ, Nakagawa S, Bahima EG, Fernández-Blanco Á, Pesaresi M, D'Antin JC, Sebastian-Perez R, Greco D, Domínguez-Sala E, Gómez-Riera R, Compte RIB, Dierssen M, Montserrat Pulido, N, Cosma MP, (2022). Müller glia fused with adult stem cells undergo neural differentiation in human retinal models Ebiomedicine 77, 103914

Visual impairments are a critical medical hurdle to be addressed in modern society. Müller glia (MG) have regenerative potential in the retina in lower vertebrates, but not in mammals. However, in mice, in vivo cell fusion between MG and adult stem cells forms hybrids that can partially regenerate ablated neurons.We used organotypic cultures of human retina and preparations of dissociated cells to test the hypothesis that cell fusion between human MG and adult stem cells can induce neuronal regeneration in human systems. Moreover, we established a microinjection system for transplanting human retinal organoids to demonstrate hybrid differentiation.We first found that cell fusion occurs between MG and adult stem cells, in organotypic cultures of human retina as well as in cell cultures. Next, we showed that the resulting hybrids can differentiate and acquire a proto-neural electrophysiology profile when the Wnt/beta-catenin pathway is activated in the adult stem cells prior fusion. Finally, we demonstrated the engraftment and differentiation of these hybrids into human retinal organoids.We show fusion between human MG and adult stem cells, and demonstrate that the resulting hybrid cells can differentiate towards neural fate in human model systems. Our results suggest that cell fusion-mediated therapy is a potential regenerative approach for treating human retinal dystrophies.This work was supported by La Caixa Health (HR17-00231), Velux Stiftung (976a) and the Ministerio de Ciencia e Innovación, (BFU2017-86760-P) (AEI/FEDER, UE), AGAUR (2017 SGR 689, 2017 SGR 926).Published by Elsevier B.V.

JTD Keywords: cell fusion, expression, fusion, ganglion-cells, in-vitro, mouse, müller glia, neural differentiation, organoids, regeneration, retina regeneration, stem cells, stromal cells, transplantation, 4',6 diamidino 2 phenylindole, 5' nucleotidase, Agarose, Alcohol, Arpe-19 cell line, Article, Beta catenin, Beta tubulin, Bone-marrow-cells, Bromophenol blue, Buffer, Calcium cell level, Calcium phosphate, Calretinin, Canonical wnt signaling, Cd34 antigen, Cell culture, Cell fusion, Cell viability, Coculture, Complementary dna, Confocal microscopy, Cornea transplantation, Cryopreservation, Cryoprotection, Crystal structure, Current clamp technique, Dimethyl sulfoxide, Dodecyl sulfate sodium, Edetic acid, Electrophysiology, Endoglin, Fetal bovine serum, Fibroblast growth factor 2, Flow cytometry, Fluorescence activated cell sorting, Fluorescence intensity, Glyceraldehyde 3 phosphate dehydrogenase, Glycerol, Glycine, Hoe 33342, Immunofluorescence, Immunohistochemistry, Incubation time, Interleukin 1beta, Lentivirus vector, Matrigel, Mercaptoethanol, Microinjection, Mueller cell, Müller glia, N methyl dextro aspartic acid, Nerve cell differentiation, Neural differentiation, Nitrogen, Nonhuman, Organoids, Paraffin, Paraffin embedding, Paraformaldehyde, Patch clamp technique, Penicillin derivative, Phenolsulfonphthalein, Phenotype, Phosphate buffered saline, Phosphoprotein phosphatase inhibitor, Polyacrylamide gel electrophoresis, Potassium chloride, Povidone iodine, Promoter region, Proteinase inhibitor, Real time polymerase chain reaction, Receptor type tyrosine protein phosphatase c, Restriction endonuclease, Retina, Retina dystrophy, Retina regeneration, Retinol, Rhodopsin, Rna extraction, Stem cell, Stem cells, Subcutaneous fat, Tunel assay, Visual impairment, Western blotting

García-Torres, Jose, Lázaro, Carmen, Sylla, Dioulde, Lanzalaco, Sonia, Ginebra, Maria-Pau, Alemán, Carlos, (2022). Combining 2D organic and 1D inorganic nanoblocks to develop free-standing hybrid nanomembranes for conformable biosensors Journal Of Nanostructure In Chemistry ,

We report a simple approach to fabricate free-standing perforated 2D nanomembranes hosting well-ordered 1D metallic nanostructures to obtain hybrid materials with nanostructured surfaces for flexible electronics. Nanomembranes are formed by alternatively depositing perforated poly(lactic acid) (PLA) and poly(3,4-ethylenedioxythiophene) layers. Copper metallic nanowires (NWs) were incorporated into the nanoperforations of the top PLA layer by electrodeposition and further coated with silver via a transmetallation reaction. The combination of 2D polymeric nanomembranes and aligned 1D metallic NWs allows merging the flexibility and conformability of the ultrathin soft polymeric nanomembranes with the good electrical properties of metals for biointegrated electronic devices. Thus, we were able to tailor the nanomembrane surface chemistry as it was corroborated by SEM, EDX, XPS, CV, EIS and contact angle. The obtained hybrid nanomembranes were flexible and conformable showing sensing capacity towards H2O2 with good linear concentration range (0.35–10 mM), sensitivity (120 µA cm?2 mM?1) and limit of detection (7 ?m). Moreover, the membranes showed good stability, reproducibility and selectivity towards H2O2.

JTD Keywords: biointegrated sensors, designs, electronics, fabrication, free-standing films, h2o2, metallic nanowires, nanoparticles, nanowires, sensor, skin, Hydrogen-peroxide, Perforated nanomembranes

Dhiman, Shikha, Andrian, Teodora, Gonzalez, Beatriz Santiago, Tholen, Marrit ME., Wang, Yuyang, Albertazzi, Lorenzo, (2022). Can super-resolution microscopy become a standard characterization technique for materials chemistry? Chemical Science 13, 2152-2166

The characterization of newly synthesized materials is a cornerstone of all chemistry and nanotechnology laboratories. For this purpose, a wide array of analytical techniques have been standardized and are used routinely by laboratories across the globe. With these methods we can understand the structure, dynamics and function of novel molecular architectures and their relations with the desired performance, guiding the development of the next generation of materials. Moreover, one of the challenges in materials chemistry is the lack of reproducibility due to improper publishing of the sample preparation protocol. In this context, the recent adoption of the reporting standard MIRIBEL (Minimum Information Reporting in Bio–Nano Experimental Literature) for material characterization and details of experimental protocols aims to provide complete, reproducible and reliable sample preparation for the scientific community. Thus, MIRIBEL should be immediately adopted in publications by scientific journals to overcome this challenge. Besides current standard spectroscopy and microscopy techniques, there is a constant development of novel technologies that aim to help chemists unveil the structure of complex materials. Among them super-resolution microscopy (SRM), an optical technique that bypasses the diffraction limit of light, has facilitated the study of synthetic materials with multicolor ability and minimal invasiveness at nanometric resolution. Although still in its infancy, the potential of SRM to unveil the structure, dynamics and function of complex synthetic architectures has been highlighted in pioneering reports during the last few years. Currently, SRM is a sophisticated technique with many challenges in sample preparation, data analysis, environmental control and automation, and moreover the instrumentation is still expensive. Therefore, SRM is currently limited to expert users and is not implemented in characterization routines. This perspective discusses the potential of SRM to transition from a niche technique to a standard routine method for material characterization. We propose a roadmap for the necessary developments required for this purpose based on a collaborative effort from scientists and engineers across disciplines.

JTD Keywords: blinking, fluorophore, intramolecular spirocyclization, localization, nanoparticles, resolution limit, reveals, single-molecule fluorescence, stimulated-emission, Characterization techniques, Diffraction, Distributed computer systems, Environmental management, Information reporting, Material chemistry, Materials characterization, Minimum information, Optical reconstruction microscopy, Optical resolving power, Sample preparation, Structure dynamics, Structure functions, Super-resolution microscopy, Synthesized materials

Georgiev VN, Avalos-Padilla Y, Fernàndez-Busquets X, Dimova R, (2022). Femtoliter Injection of ESCRT-III Proteins into Adhered Giant Unilamellar Vesicles Bio Protoc 12, e4328

The endosomal sorting complex required for transport (ESCRT) machinery mediates membrane fission reactions that exhibit a different topology from that observed in clathrin-coated vesicles. In all of the ESCRT-mediated events, the nascent vesicle buds away from the cytosol. However, ESCRT proteins are able to act upon membranes with different geometries. For instance, the formation of multivesicular bodies (MVBs) and the biogenesis of extracellular vesicles both require the participation of the ESCRT-III sub-complex, and they differ in their initial membrane geometry before budding starts: the protein complex acts either from outside the membrane organelle (causing inward budding) or from within (causing outward budding). Several studies have reconstituted the action of the ESCRT-III subunits in supported bilayers and cell-sized vesicles mimicking the geometry occurring during MVBs formation (in-bud), but extracellular vesicle budding (out-bud) mechanisms remain less explored, because of the outstanding difficulties encountered in encapsulation of functional ESCRT-III in vesicles. Here, we provide a different approach that allows the recreation of the out-bud formation, by combining giant unilamellar vesicles as a membrane model and a microinjection system. The vesicles are immobilized prior to injection via weak adhesion to the chamber coverslip, which also ensures preserving the membrane excess area required for budding. After protein injection, vesicles exhibit outward budding. The approach presented in this work can be used in the future to disentangle the mechanisms underlying ESCRT-III-mediated fission, recreating the geometry of extracellular bud production, which remains a challenge. Moreover, the microinjection methodology can be also adapted to interrogate the action of other cytosolic components on the encapsulating membranous organelle. Copyright: © 2022 The Authors.

JTD Keywords: adhesion, budding, electroformation, escrt-iii, exosomes, extracellular vesicles, light, microinjection, microparticles, plasma, Adhesion, Budding, Escrt-iii, Extracellular vesicles, Giant unilamellar vesicle (guv), Membrane, Microinjection

Bar L, Perissinotto F, Redondo-Morata L, Giannotti MI, Goole J, Losada-Pérez P, (2022). Interactions of hydrophilic quantum dots with defect-free and defect containing supported lipid membranes Colloids And Surfaces B-Biointerfaces 210, 112239

Quantum dots (QDs) are semiconductor nanoparticles with unique optical and electronic properties, whose interest as potential nano-theranostic platforms for imaging and sensing is increasing. The design and use of QDs requires the understanding of cell-nanoparticle interactions at a microscopic and nanoscale level. Model systems such as supported lipid bilayers (SLBs) are useful, less complex platforms mimicking physico-chemical properties of cell membranes. In this work, we investigated the effect of topographical homogeneity of SLBs bearing different surface charge in the adsorption of hydrophilic QDs. Using quartz-crystal microbalance, a label-free surface sensitive technique, we show significant differences in the interactions of QDs onto homogeneous and inhomogeneous SLBs formed following different strategies. Within short time scales, QDs adsorb onto topographically homogeneous, defect-free SLBs is driven by electrostatic interactions, leading to no layer disruption. After prolonged QD exposure, the nanomechanical stability of the SLB decreases suggesting nanoparticle insertion. In the case of inhomogeneous, defect containing layers, QDs target preferentially membrane defects, driven by a subtle interplay of electrostatic and entropic effects, inducing local vesicle rupture and QD insertion at membrane edges. © 2021

JTD Keywords: adsorption, atomic force microscopy, bilayer formation, gold nanoparticles, hydrophilic quantum dots, lipid membrane defects, model, nanomechanics, quartz crystal microbalance with dissipation, size, supported lipid bilayers, surfaces, Atomic force microscopy, Atomic-force-microscopy, Cytology, Defect-free, Electronic properties, Electrostatics, Hydrophilic quantum dot, Hydrophilic quantum dots, Hydrophilicity, Hydrophilics, Lipid bilayers, Lipid membrane defect, Lipid membrane defects, Lipid membranes, Lipids, Nanocrystals, Nanomechanics, Optical and electronic properties, Quartz, Quartz crystal microbalance with dissipation, Quartz crystal microbalances, Quartz-crystal microbalance, Semiconductor nanoparticles, Semiconductor quantum dots, Supported lipid bilayers

Beltrán G, Navajas D, García-Aznar JM, (2022). Mechanical modeling of lung alveoli: From macroscopic behaviour to cell mechano-sensing at microscopic level Journal Of The Mechanical Behavior Of Biomedical Materials 126, 105043

The mechanical signals sensed by the alveolar cells through the changes in the local matrix stiffness of the extracellular matrix (ECM) are determinant for regulating cellular functions. Therefore, the study of the mechanical response of lung tissue becomes a fundamental aspect in order to further understand the mechanosensing signals perceived by the cells in the alveoli. This study is focused on the development of a finite element (FE) model of a decellularized rat lung tissue strip, which reproduces accurately the mechanical behaviour observed in the experiments by means of a tensile test. For simulating the complex structure of the lung parenchyma, which consists of a heterogeneous and non-uniform network of thin-walled alveoli, a 3D model based on a Voronoi tessellation is developed. This Voronoi-based model is considered very suitable for recreating the geometry of cellular materials with randomly distributed polygons like in the lung tissue. The material model used in the mechanical simulations of the lung tissue was characterized experimentally by means of AFM tests in order to evaluate the lung tissue stiffness on the micro scale. Thus, in this study, the micro (AFM test) and the macro scale (tensile test) mechanical behaviour are linked through the mechanical simulation with the 3D FE model based on Voronoi tessellation. Finally, a micro-mechanical FE-based model is generated from the Voronoi diagram for studying the stiffness sensed by the alveolar cells in function of two independent factors: the stretch level of the lung tissue and the geometrical position of the cells on the extracellular matrix (ECM), distinguishing between pneumocyte type I and type II. We conclude that the position of the cells within the alveolus has a great influence on the local stiffness perceived by the cells. Alveolar cells located at the corners of the alveolus, mainly type II pneumocytes, perceive a much higher stiffness than those located in the flat areas of the alveoli, which correspond to type I pneumocytes. However, the high stiffness, due to the macroscopic lung tissue stretch, affects both cells in a very similar form, thus no significant differences between them have been observed. © 2021 The Authors

JTD Keywords: rat, scaffolds, stiffness, Afm, Animal cell, Animal experiment, Animal model, Animal tissue, Article, Biological organs, Cell function, Cells, Computational geometry, Cytology, Extracellular matrices, Extracellular matrix, Extracellular-matrix, Geometry, High stiffness, Human, Lung alveolus cell type 1, Lung alveolus cell type 2, Lung parenchyma, Lung tissue, Male, Mechanical behavior, Mechanical modeling, Mechanical simulations, Mechanosensing, Model-based opc, Nonhuman, Physical model, Rat, Rigidity, Stiffness, Stiffness matrix, Tensile testing, Thin walled structures, Three dimensional finite element analysis, Tissue, Type ii, Voronoi tessellations

Cascione M, Rizzello L, Manno D, Serra A, De Matteis V, (2022). Green Silver Nanoparticles Promote Inflammation Shutdown in Human Leukemic Monocytes Materials (Basel) 15, 775

The use of silver nanoparticles (Ag NPs) in the biomedical field deserves a mindful analysis of the possible inflammatory response which could limit their use in the clinic. Despite the anti-cancer properties of Ag NPs having been widely demonstrated, there are still few studies concerning their involvement in the activation of specific inflammatory pathways. The inflammatory outcome depends on the synthetic route used in the NPs production, in which toxic reagents are employed. In this work, we compared two types of Ag NPs, obtained by two different chemical routes: conventional synthesis using sodium citrate and a green protocol based on leaf extracts as a source of reduction and capping agents. A careful physicochemical characterization was carried out showing spherical and stable Ag NPs with an average size between 20 nm and 35 nm for conventional and green Ag NPs respectively. Then, we evaluated their ability to induce the activation of inflammation in Human Leukemic Monocytes (THP-1) differentiated into M0 macrophages using 1 µM and 2 µM NPs concentrations (corresponded to 0.1 µg/mL and 0.2 µg/mL respectively) and two-time points (24 h and 48 h). Our results showed a clear difference in Nuclear Factor ?B (NF-?b) activation, Interleukins 6–8 (IL-6, IL-8) secretion, Tumor Necrosis Factor-? (TNF-?) and Cyclooxygenase-2 (COX-2) expression exerted by the two kinds of Ag NPs. Green Ag NPs were definitely tolerated by macrophages compared to conventional Ag NPs which induced the activation of all the factors mentioned above. Subsequently, the exposure of breast cancer cell line (MCF-7) to the green Ag NPs showed that they exhibited antitumor activity like the conventional ones, but surprisingly, using the MCF-10A line (not tumoral breast cells) the green Ag NPs did not cause a significant decrease in cell viability. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

JTD Keywords: activation, biosynthesis, gold nanoparticles, green route, inflammation response, mechanism, metal, nanotechnology, physico-chemical properties, raman-spectroscopy, resonance, silver nanoparticles, surface, Biomedical fields, Cell culture, Cell death, Chemical activation, Chemical routes, Conventional synthesis, Diseases, Green route, Inflammation response, Inflammatory response, Macrophages, Metal nanoparticles, Nf-kappa-b, Pathology, Physico-chemical properties, Physicochemical property, Property, Silver nanoparticles, Sodium compounds, Synthetic routes, Toxic reagents

Murar M, Albertazzi L, Pujals S, (2022). Advanced Optical Imaging-Guided Nanotheranostics toward Personalized Cancer Drug Delivery Nanomaterials 12, 399

Nanomedicine involves the use of nanotechnology for clinical applications and holds promise to improve treatments. Recent developments offer new hope for cancer detection, prevention and treatment; however, being a heterogenous disorder, cancer calls for a more targeted treatment approach. Personalized Medicine (PM) aims to revolutionize cancer therapy by matching the most effective treatment to individual patients. Nanotheranostics comprise a combination of therapy and diagnostic imaging incorporated in a nanosystem and are developed to fulfill the promise of PM by helping in the selection of treatments, the objective monitoring of response and the planning of follow-up therapy. Although well-established imaging techniques, such as Magnetic Resonance Imaging (MRI), Computed Tomography (CT), Positron Emission Tomography (PET) and Single-Photon Emission Computed Tomography (SPECT), are primarily used in the development of theranostics, Optical Imaging (OI) offers some advantages, such as high sensitivity, spatial and temporal resolution and less invasiveness. Additionally, it allows for multiplexing, using multi-color imaging and DNA barcoding, which further aids in the development of personalized treatments. Recent advances have also given rise to techniques permitting better penetration, opening new doors for OI-guided nanotheranostics. In this review, we describe in detail these recent advances that may be used to design and develop efficient and specific nanotheranostics for personalized cancer drug delivery. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

JTD Keywords: 5-aminolevulinic acid, cancer, contrast agents, in-vivo, malignant gliomas, multifunctional nanoparticles, nanomedicine, optical imaging, ovarian-cancer, personalized medicine, quantum dots, silica nanoparticles, targeted probes, theranostics, Cancer, Nanomedicine, Optical imaging, Personalized medicine, Superparamagnetic iron-oxide, Theranostics

Kadkhodaie-Elyaderani A, de Lama-Odría MC, Rivas M, Martínez-Rovira I, Yousef I, Puiggalí J, Del Valle LJ, (2022). Medicated Scaffolds Prepared with Hydroxyapatite/Streptomycin Nanoparticles Encapsulated into Polylactide Microfibers International Journal Of Molecular Sciences 23, 1282

The preparation, characterization, and controlled release of hydroxyapatite (HAp) nanopar-ticles loaded with streptomycin (STR) was studied. These nanoparticles are highly appropriate for the treatment of bacterial infections and are also promising for the treatment of cancer cells. The analyses involved scanning electron microscopy, dynamic light scattering (DLS) and Z-potential measurements, as well as infrared spectroscopy and X-ray diffraction. Both amorphous (ACP) and crystalline (cHAp) hydroxyapatite nanoparticles were considered since they differ in their release behavior (faster and slower for amorphous and crystalline particles, respectively). The encapsulated nanoparticles were finally incorporated into biodegradable and biocompatible polylactide (PLA) scaf-folds. The STR load was carried out following different pathways during the synthesis/precipitation of the nanoparticles (i.e., nucleation steps) and also by simple adsorption once the nanoparticles were formed. The loaded nanoparticles were biocompatible according to the study of the cytotoxicity of extracts using different cell lines. FTIR microspectroscopy was also employed to evaluate the cytotoxic effect on cancer cell lines of nanoparticles internalized by endocytosis. The results were promising when amorphous nanoparticles were employed. The nanoparticles loaded with STR increased their size and changed their superficial negative charge to positive. The nanoparticles’ crystallinity decreased, with the consequence that their crystal sizes reduced, when STR was incorporated into their structure. STR maintained its antibacterial activity, although it was reduced during the adsorption into the nanoparticles formed. The STR release was faster from the amorphous ACP nanoparticles and slower from the crystalline cHAp nanoparticles. However, in both cases, the STR release was slower when incorporated in calcium and phosphate during the synthesis. The biocompatibility of these nanoparticles was assayed by two approximations. When extracts from the nanoparticles were evaluated in cultures of cell lines, no cytotoxic damage was observed at concen-trations of less than 10 mg/mL. This demonstrated their biocompatibility. Another experiment using FTIR microspectroscopy evaluated the cytotoxic effect of nanoparticles internalized by endocytosis in cancer cells. The results demonstrated slight damage to the biomacromolecules when the cells were treated with ACP nanoparticles. Both ACP and cHAp nanoparticles were efficiently encapsulated in PLA electrospun matrices, providing functionality and bioactive properties. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

JTD Keywords: antibiotics, antimicrobial activity, behavior, cytotoxicity, delivery, drug, drug delivery, hydroxyapatite nanoparticles, in-vitro, mechanisms, mitochondria, polylactide, release, streptomycin, Antimicrobial activity, Cancer stem-cells, Cytotoxicity, Drug delivery, Hydroxyapatite nanoparticles, Polylactide, Streptomycin

Dias JMS, Estima D, Punte H, Klingner A, Marques L, Magdanz V, Khalil ISM, (2022). Modeling and Characterization of the Passive Bending Stiffness of Nanoparticle-Coated Sperm Cells using Magnetic Excitation Advanced Theory And Simulations 5, 2100438

Of all the various locomotion strategies in low- (Formula presented.), traveling-wave propulsion methods with an elastic tail are preferred because they can be developed using simple designs and fabrication procedures. The only intrinsic property of the elastic tail that governs the form and rate of wave propagation along its length is the bending stiffness. Such traveling wave motion is performed by spermatozoa, which possess a tail that is characterized by intrinsic variable stiffness along its length. In this paper, the passive bending stiffness of the magnetic nanoparticle-coated flagella of bull sperm cells is measured using a contactless electromagnetic-based excitation method. Numerical elasto-hydrodynamic models are first developed to predict the magnetic excitation and relaxation of nanoparticle-coated nonuniform flagella. Then solutions are provided for various groups of nonuniform flagella with disparate nanoparticle coatings that relate their bending stiffness to their decay rate after the magnetic field is removed and the flagellum restores its original configuration. The numerical models are verified experimentally, and capture the effect of the nanoparticle coating on the bending stiffness. It is also shown that electrostatic self-assembly enables arbitrarily magnetizable cellular segments with variable stiffness along the flagellum. The bending stiffness is found to depend on the number and location of the magnetized cellular segments. © 2022 The Authors. Advanced Theory and Simulations published by Wiley-VCH GmbH.

JTD Keywords: Bending stiffness, Cells, Cellulars, Coatings, Decay (organic), Electric excitation, Excited states, Flagellar propulsion, Locomotion strategies, Low reynolds numbers, Magnetic, Magnetic excitations, Nanoparticle coatings, Passive, Propulsion methods, Self assembly, Simple++, Sperm cell, Sperm cells, Stiffness, Travelling waves, Variable stiffness, Wave propagation

Boloix, A, Feiner-Gracia, N, Kober, M, Repetto, J, Pascarella, R, Soriano, A, Masanas, M, Segovia, N, Vargas-Nadal, G, Merlo-Mas, J, Danino, D, Abutbul-Ionita, I, Foradada, L, Roma, J, Cordoba, A, Sala, S, Toledo, JS, Gallego, S, Veciana, J, Albertazzi, L, Segura, MF, Ventosa, N, (2022). Engineering pH-Sensitive Stable Nanovesicles for Delivery of MicroRNA Therapeutics Small 18, 2101959

MicroRNAs (miRNAs) are small non-coding endogenous RNAs, which are attracting a growing interest as therapeutic molecules due to their central role in major diseases. However, the transformation of these biomolecules into drugs is limited due to their unstability in the bloodstream, caused by nucleases abundantly present in the blood, and poor capacity to enter cells. The conjugation of miRNAs to nanoparticles (NPs) could be an effective strategy for their clinical delivery. Herein, the engineering of non-liposomal lipid nanovesicles, named quatsomes (QS), for the delivery of miRNAs and other small RNAs into the cytosol of tumor cells, triggering a tumor-suppressive response is reported. The engineered pH-sensitive nanovesicles have controlled structure (unilamellar), size (<150 nm) and composition. These nanovesicles are colloidal stable (>24 weeks), and are prepared by a green, GMP compliant, and scalable one-step procedure, which are all unavoidable requirements for the arrival to the clinical practice of NP based miRNA therapeutics. Furthermore, QS protect miRNAs from RNAses and when injected intravenously, deliver them into liver, lung, and neuroblastoma xenografts tumors. These stable nanovesicles with tunable pH sensitiveness constitute an attractive platform for the efficient delivery of miRNAs and other small RNAs with therapeutic activity and their exploitation in the clinics.

JTD Keywords: cancer therapy, mirnas delivery, nanocarriers, nanovesicles, neuroblastoma, pediatric cancer, quatsomes, Biodistribution, Cancer therapy, Cell engineering, Cells, Cholesterol, Controlled drug delivery, Diseases, Dna, Dysregulated ph, Lipoplex, Microrna delivery, Mirnas delivery, Nanocarriers, Nanoparticles, Nanovesicle, Nanovesicles, Neuroblastoma, Neuroblastomas, Pediatric cancer, Ph sensitive, Ph sensors, Quatsome, Quatsomes, Rna, Sirna, Sirna delivery, Sirnas delivery, Small interfering rna, Small rna, Targeted drug delivery, Tumors, Vesicles

Arista-Romero M, Delcanale P, Pujals S, Albertazzi L, (2022). Nanoscale Mapping of Recombinant Viral Proteins: From Cells to Virus-Like Particles Acs Photonics 9, 101-109

Influenza recombinant proteins and virus-like particles (VLPs) play an important role in vaccine development (e.g., CadiFluS). However, their production from mammalian cells suffers from low yields and lack of control of the final VLPs. To improve these issues, characterization techniques able to visualize and quantify the different steps of the process are needed. Fluorescence microscopy represents a powerful tool able to image multiple protein targets; however, its limited resolution hinders the study of viral constructs. Here, we propose the use of super-resolution microscopy and in particular of DNA-point accumulation for imaging in nanoscale topography (DNA-PAINT) microscopy as a characterization method for recombinant viral proteins on both cells and VLPs. We were able to quantify the amount of the three main influenza proteins (hemagglutinin (HA), neuraminidase (NA), and ion channel matrix protein 2 (M2)) per cell and per VLP with nanometer resolution and single-molecule sensitivity, proving that DNA-PAINT is a powerful technique to characterize recombinant viral constructs.

JTD Keywords: dna-paint, hemagglutinin, influenza, neuraminidase, paint, recombinant proteins, single-molecule localization microscopy, single-particle analysis, virus-like particles, Dna-paint, Hemagglutinin, Influenza, Neuraminidase, Paint, Recombinant proteins, Single particle analysis, Single-molecule localization microscopy, Single-particle analysis, Super-resolution microscopy, Superresolution microscopy, Virus-like particles

Gawish R, Starkl P, Pimenov L, Hladik A, Lakovits K, Oberndorfer F, Cronin SJF, Ohradanova-Repic A, Wirnsberger G, Agerer B, Endler L, Capraz T, Perthold JW, Cikes D, Koglgruber R, Hagelkruys A, Montserrat N, Mirazimi A, Boon L, Stockinger H, Bergthaler A, Oostenbrink C, Penninger JM, Knapp S, (2022). ACE2 is the critical in vivo receptor for SARS-CoV-2 in a novel COVID-19 mouse model with TNF-and IFNy-driven immunopathology Elife 11, e74623

Despite tremendous progress in the understanding of COVID-19, mechanistic insight into immunological, disease-driving factors remains limited. We generated maVie16, a mouse-adapted SARS-CoV-2, by serial passaging of a human isolate. In silico modeling revealed how only three Spike mutations of maVie16 enhanced interaction with murine ACE2. maVie16 induced profound pathology in BALB/c and C57BL/6 mice, and the resulting mouse COVID-19 (mCOVID-19) replicated critical aspects of human disease, including early lymphopenia, pulmonary immune cell infiltration, pneumonia, and specific adaptive immunity. Inhibition of the proinflammatory cyto-kines IFN? and TNF substantially reduced immunopathology. Importantly, genetic ACE2-deficiency completely prevented mCOVID-19 development. Finally, inhalation therapy with recombinant ACE2 fully protected mice from mCOVID-19, revealing a novel and efficient treatment. Thus, we here present maVie16 as a new tool to model COVID-19 for the discovery of new therapies and show that disease severity is determined by cytokine-driven immunopathology and critically dependent on ACE2 in vivo. © Gawish et al.

JTD Keywords: covid-19 mouse model, covid-19 therapy, cytokine storm, mavie16, mouse, program, recombinant soluble ace2, tmprss2, Adaptive immunity, Angiotensin converting enzyme 2, Angiotensin-converting enzyme 2, Animal, Animal cell, Animal experiment, Animal model, Animal tissue, Animals, Apoptosis, Article, Bagg albino mouse, Breathing rate, Bronchoalveolar lavage fluid, C57bl mouse, Cell composition, Cell infiltration, Controlled study, Coronavirus disease 2019, Coronavirus spike glycoprotein, Covid-19, Cytokeratin 18, Cytokine production, Dipeptidyl carboxypeptidase, Disease model, Disease models, animal, Disease severity, Drosophila-melanogaster, Enzyme linked immunosorbent assay, Expression vector, Flow cytometry, Gamma interferon, Gene editing, Gene expression, Gene mutation, Genetic engineering, Genetics, Glycosylation, High mobility group b1 protein, Histology, Histopathology, Immune response, Immunocompetent cell, Immunology, Immunopathology, Interferon-gamma, Interleukin 2, Metabolism, Mice, inbred balb c, Mice, inbred c57bl, Mouse-adapted sars-cov-2, Myeloperoxidase, Neuropilin 1, Nonhuman, Nucleocapsid protein, Pathogenicity, Peptidyl-dipeptidase a, Pyroptosis, Renin angiotensin aldosterone system, Rna extraction, Rna isolation, Sars-cov-2, Severe acute respiratory syndrome coronavirus 2, Spike glycoprotein, coronavirus, T lymphocyte activation, Trabecular meshwork, Tumor necrosis factor, Virology, Virus load, Virus replication, Virus transmission, Virus virulence

McGill, Kris, Sackley, Catherine, Godwin, Jon, Gavaghan, David, Ali, Myzoon, Ballester, Belen Rubio, Brady, Marian C, Brady, M.C, Ali, M, Ashburn, A, Barer, D, Barzel, A, Bernhardt, J, Bowen, A, Drummond, A, Edmans, J, English, C, Gladman, J, Godecke, E, Hiekkala, S, Hoffman, T, Kalra, L, Kuys, S, Langhorne, P, Laska, A.C, Lees, K, Logan, P, Machner, B, Mead, G, Morris, J, Pandyan, A, Pollock, A, Pomeroy, V, Rodgers, H, Sackley, C, Shaw, L, Stott, D.J, Sunnerhagen, K.S, Tyson, S, van Vliet, P, Walker, M, Whiteley, W, (2022). Using the Barthel Index and modified Rankin Scale as Outcome Measures for Stroke Rehabilitation Trials; A Comparison of Minimum Sample Size Requirements Journal Of Stroke & Cerebrovascular Diseases 31, 106229

Underpowered trials risk inaccurate results. Recruitment to stroke rehabilitation randomised controlled trials (RCTs) is often a challenge. Statistical simulations offer an important opportunity to explore the adequacy of sample sizes in the context of specific outcome measures. We aimed to examine and compare the adequacy of stroke rehabilitation RCT sample sizes using the Barthel Index (BI) or modified Rankin Scale (mRS) as primary outcomes.We conducted computer simulations using typical experimental event rates (EER) and control event rates (CER) based on individual participant data (IPD) from stroke rehabilitation RCTs. Event rates are the proportion of participants who experienced clinically relevant improvements in the RCT experimental and control groups. We examined minimum sample size requirements and estimated the number of participants required to achieve a number needed to treat within clinically acceptable boundaries for the BI and mRS.We secured 2350 IPD (18 RCTs). For a 90% chance of statistical accuracy on the BI a rehabilitation RCT would require 273 participants per randomised group. Accurate interpretation of effect sizes would require 1000s of participants per group. Simulations for the mRS were not possible as a clinically relevant improvement was not detected when using this outcome measure.Stroke rehabilitation RCTs with large sample sizes are required for accurate interpretation of effect sizes based on the BI. The mRS lacked sensitivity to detect change and thus may be unsuitable as a primary outcome in stroke rehabilitation trials.Copyright © 2021 Elsevier Inc. All rights reserved.

JTD Keywords: barthel index, randomised controlled trials, recruitment, sample size calculations, simulations, stroke rehabilitation, Adult, Article, Barthel index, Calculation, Computer simulation, Controlled study, Effect size, Female, Human, Human experiment, Major clinical study, Male, Modified rankin scale, Numbers needed to treat, Outcome assessment, Randomised controlled trials, Randomized controlled trial, Rankin scale, Recruitment, Rehabilitation, Sample size, Sample size calculations, Simulations, Stroke rehabilitation

Guallar-Garrido, Sandra, Almiñana-Rapún, Farners, Campo-Pérez, Víctor, Torrents, Eduard, Luquin, Marina, Julián, Esther, (2022). BCG Substrains Change Their Outermost Surface as a Function of Growth Media Vaccines 10, 40

Mycobacterium bovis bacillus Calmette-Guérin (BCG) efficacy as an immunotherapy tool can be influenced by the genetic background or immune status of the treated population and by the BCG substrain used. BCG comprises several substrains with genetic differences that elicit diverse phenotypic characteristics. Moreover, modifications of phenotypic characteristics can be influenced by culture conditions. However, several culture media formulations are used worldwide to produce BCG. To elucidate the influence of growth conditions on BCG characteristics, five different substrains were grown on two culture media, and the lipidic profile and physico-chemical properties were evaluated. Our results show that each BCG substrain displays a variety of lipidic profiles on the outermost surface depending on the growth conditions. These modifications lead to a breadth of hydrophobicity patterns and a different ability to reduce neutral red dye within the same BCG substrain, suggesting the influence of BCG growth conditions on the interaction between BCG cells and host cells.

JTD Keywords: cell wall, efficacy, glycerol, hydrophobicity, lipid, neutral red, pdim, pgl, protein, strains, viability, virulence, Acylglycerol, Albumin, Article, Asparagine, Bacterial cell wall, Bacterial gene, Bacterium culture, Bcg vaccine, Catalase, Cell wall, Chloroform, Controlled study, Escherichia coli, Gene expression, Genomic dna, Glycerol, Glycerol monomycolate, Hexadecane, Housekeeping gene, Hydrophobicity, Immune response, Immunogenicity, Immunotherapy, Lipid, Lipid fingerprinting, Magnesium sulfate, Mercaptoethanol, Methanol, Methylglyoxal, Molybdatophosphoric acid, Mycobacterium bovis bcg, Neutral red, Nonhuman, Pdim, Petroleum ether, Pgl, Phenotype, Physical chemistry, Real time reverse transcription polymerase chain reaction, Rna 16s, Rna extraction, Rv0577, Staining, Thin layer chromatography, Unclassified drug

Ballester, BR, Antenucci, F, Maier, M, Coolen, ACC, Verschure, PFMJ, (2021). Estimating upper-extremity function from kinematics in stroke patients following goal-oriented computer-based training Journal Of Neuroengineering And Rehabilitation 18, 186

Introduction: After a stroke, a wide range of deficits can occur with varying onset latencies. As a result, assessing impairment and recovery are enormous challenges in neurorehabilitation. Although several clinical scales are generally accepted, they are time-consuming, show high inter-rater variability, have low ecological validity, and are vulnerable to biases introduced by compensatory movements and action modifications. Alternative methods need to be developed for efficient and objective assessment. In this study, we explore the potential of computer-based body tracking systems and classification tools to estimate the motor impairment of the more affected arm in stroke patients. Methods: We present a method for estimating clinical scores from movement parameters that are extracted from kinematic data recorded during unsupervised computer-based rehabilitation sessions. We identify a number of kinematic descriptors that characterise the patients' hemiparesis (e.g., movement smoothness, work area), we implement a double-noise model and perform a multivariate regression using clinical data from 98 stroke patients who completed a total of 191 sessions with RGS. Results: Our results reveal a new digital biomarker of arm function, the Total Goal-Directed Movement (TGDM), which relates to the patients work area during the execution of goal-oriented reaching movements. The model's performance to estimate FM-UE scores reaches an accuracy of R-2: 0.38 with an error (sigma: 12.8). Next, we evaluate its reliability (r = 0.89 for test-retest), longitudinal external validity (95% true positive rate), sensitivity, and generalisation to other tasks that involve planar reaching movements (R-2: 0.39). The model achieves comparable accuracy also for the Chedoke Arm and Hand Activity Inventory (R-2: 0.40) and Barthel Index (R-2: 0.35). Conclusions: Our results highlight the clinical value of kinematic data collected during unsupervised goal-oriented motor training with the RGS combined with data science techniques, and provide new insight into factors underlying recovery and its biomarkers.

JTD Keywords: interactive feedback, motion classification, motion sensing, multivariate regression, posture monitoring, rehabilitation, stroke, Adult, Aged, Analytic method, Arm movement, Article, Barthel index, Brain hemorrhage, Cerebrovascular accident, Chedoke arm and hand activity inventory, Clinical protocol, Cognitive defect, Computer analysis, Controlled study, Convergent validity, Correlation coefficient, Disease severity, External validity, Female, Fugl meyer assessment for the upper extremity, Functional assessment, Functional status assessment, General health status assessment, Hemiparesis, Human, Interactive feedback, Ischemic stroke, Kinematics, Major clinical study, Male, Mini mental state examination, Motion classification, Motion sensing, Motor analog scale, Movement, Multivariate regression, Muscle function, Posture monitoring, Probability, Recovery, Rehabilitation, Reliability, Retrospective study, Stroke, Stroke patient, Test retest reliability, Therapy, Total goal directed movement, Upper extremities, Upper limb, Upper-limb, Wolf motor function test

Dulay, S, Rivas, L, Pla, L, Berdun, S, Eixarch, E, Gratacos, E, Illa, M, Mir, M, Samitier, J, (2021). Fetal ischemia monitoring with in vivo implanted electrochemical multiparametric microsensors Journal Of Biological Engineering 15, 28

Under intrauterine growth restriction (IUGR), abnormal attainment of the nutrients and oxygen by the fetus restricts the normal evolution of the prenatal causing in many cases high morbidity being one of the top-ten causes of neonatal death. The current gold standards in hospitals to detect this relevant problem is the clinical observation by echography, cardiotocography and Doppler. These qualitative techniques are not conclusive and requires risky invasive fetal scalp blood testing and/or amniocentesis. We developed micro-implantable multiparametric electrochemical sensors for measuring ischemia in real time in fetal tissue and vascular. This implantable technology is designed to continuous monitoring for an early detection of ischemia to avoid potential fetal injury. Two miniaturized electrochemical sensors were developed based on oxygen and pH detection. The sensors were optimized in vitro under controlled concentration, to assess the selectivity and sensitivity required. The sensors were then validated in vivo in the ewe fetus model, by means of their insertion in the muscle leg and inside the iliac artery of the fetus. Ischemia was achieved by gradually obstructing the umbilical cord to regulate the amount of blood reaching the fetus. An important challenge in fetal monitoring is the detection of low levels of oxygen and pH changes under ischemic conditions, requiring high sensitivity sensors. Significant differences were observed in both; pH and pO(2) sensors under changes from normoxia to hypoxia states in the fetus tissue and vascular with both sensors. Herein, we demonstrate the feasibility of the developed sensors for future fetal monitoring in medical applications.

JTD Keywords: electrochemical biosensor, implantable sensor, in vivo validation, ischemia detection, tissue and vascular monitoring, Animal experiment, Animal model, Animal tissue, Article, Blood-gases, Brain, Classification, Controlled study, Diagnosis, Doppler, Early diagnosis, Electrochemical analysis, Electrochemical biosensor, Ewe, Feasibility study, Female, Fetus, Fetus disease, Fetus monitoring, Gestational age, Hypoxemia, Iliac artery, Implantable sensor, In vivo validation, Intrauterine growth restriction, Intrauterine growth retardation, Ischemia detection, Leg muscle, Management, Nonhuman, Oxygen consumption, Ph, Ph and oxygen detection, Ph measurement, Process optimization, Sheep, Tissue and vascular monitoring, Umbilical-cord occlusion

Andrian, T, Pujals, S, Albertazzi, L, (2021). Quantifying the effect of PEG architecture on nanoparticle ligand availability using DNA-PAINT Nanoscale Advances 3, 6876-6881

The importance of PEG architecture on nanoparticle (NP) functionality is known but still difficult to investigate, especially at a single particle level. Here, we apply DNA Point Accumulation for Imaging in Nanoscale Topography (DNA-PAINT), a super-resolution microscopy (SRM) technique, to study the surface functionality in poly(lactide-co-glycolide)-poly(ethylene glycol) (PLGA-PEG) NPs with different PEG structures. We demonstrated how the length of the PEG spacer can influence the accessibility of surface chemical functionality, highlighting the importance of SRM techniques to support the rational design of functionalized NPs.

JTD Keywords: chain-length, density, plga, surface, systems, Chain-length, Density, Dna, Microscopy technique, Nanoparticles, Nanoscale topography, Paint, Peg spacers, Plga, Poly lactide-co-glycolide, Poly-lactide-co-glycolide, Polyethylene glycols, Polylactide-co-glycolide, Single-particle, Super-resolution microscopy, Superresolution microscopy, Surface, Surface chemicals, Surface functionalities, Systems

Vukomanovic M, Cendra MdM, Baelo A, Torrents E, (2021). Nano-engineering stable contact-based antimicrobials: Chemistry at the interface between nano-gold and bacteria Colloids And Surfaces B-Biointerfaces 208, 112083

Contact-based antimicrobials, as antibiotic-free technologies that use non-specific interactions with bacterial cells to exert antimicrobial activity, are a prospective solution in fighting the global issue of bacterial resistance. A very simplified approach to their design considers the direct bonding of cationic guanidine-containing amino acids to the surface of nano-gold carriers. The structure enables antimicrobial activity due to a high density of cationic surface charges. This opens a set of novel questions that are important for their effective engineering, particularly regarding (i) chemistry and events that take place at the interface between NPs and cells, (ii) the direct influence of a charge (and its change) on interactions with bacterial and mammalian cells, and (iii) the stability of structures (and their antimicrobial activity) in the presence of enzymes, which are addressed in this paper. Because of the ability of amino acid-functionalized nano-gold to retain structural and functional activity, even after exposure to a range of physicochemical stimuli, they provide an excellent nanotechnological platform for designing highly effective contact-based antimicrobials and their applications.

JTD Keywords: agents, antibiotic-free technology, arginine, charged amino acids, contact-based antimicrobials, discovery, enzyme-resistant antimicrobials, functionalized gold, peptides, polymers, resistant, Antibiotic-free technology, Charged amino acids, Contact-based antimicrobials, Enzyme-resistant antimicrobials, Functionalized gold, Nanoparticles

Farré R, Rodríguez-Lázaro MA, Dinh-Xuan AT, Pons-Odena M, Navajas D, Gozal D, (2021). A low-cost, easy-to-assemble device to prevent infant hyperthermia under conditions of high thermal stress International Journal Of Environmental Research And Public Health 18, 13382

High ambient temperature and humidity greatly increase the risk of hyperthermia and mortality, particularly in infants, who are especially prone to dehydration. World areas at high risk of heat stress include many of the low-and middle-income countries (LMICs) where most of their inhabitants have no access to air conditioning. This study aimed to design, evaluate, and test a novel low-cost and easy-to-assemble device aimed at preventing the risk of infant hyperthermia in LMICs. The device is based on optimizing negative heat transfer from a small amount of ice and transferring it directly to the infant by airflow of refrigerated air. As a proof of concept, a device was assembled mainly using recycled materials, and its performance was assessed under laboratory-controlled conditions in a climatic chamber mimicking realistic stress conditions of high temperature and humidity. The device, which can be assembled by any layperson using easily available materials, provided sufficient refrigerating capacity for several hours from just 1–2 kg of ice obtained from a domestic freezer. Thus, application of this novel device may serve to attenuate the adverse effects of heat stress in infants, particularly in the context of the evolving climatic change trends. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

JTD Keywords: air conditioning, ambient-temperature, death, heat, heat index, heat shock, heatwave, high ambient temperature, hyperthermia, low-cost refrigeration, low-middle income countries, mortality, negative heat transfer, Air conditioning, Algorithm, Article, Climate change, Cost benefit analysis, Environmental temperature, Heat index, Heat shock, Heat stress, Heat transfer, Heating, Heatwave, High ambient temperature, High temperature, Humidity, Hyperthermia, Low income country, Low-cost refrigeration, Low-middle income countries, Middle income country, Middle-income countries, Negative heat transfer, Prevention study, Refrigeration, Temperature stress, Thawing

Guasch-Girbau A, Fernàndez-Busquets X, (2021). Review of the current landscape of the potential of nanotechnology for future malaria diagnosis, treatment, and vaccination strategies Pharmaceutics 13, 2189

Malaria eradication has for decades been on the global health agenda, but the causative agents of the disease, several species of the protist parasite Plasmodium, have evolved mechanisms to evade vaccine-induced immunity and to rapidly acquire resistance against all drugs entering clinical use. Because classical antimalarial approaches have consistently failed, new strategies must be explored. One of these is nanomedicine, the application of manipulation and fabrication technology in the range of molecular dimensions between 1 and 100 nm, to the development of new medical solutions. Here we review the current state of the art in malaria diagnosis, prevention, and therapy and how nanotechnology is already having an incipient impact in improving them. In the second half of this review, the next generation of antimalarial drugs currently in the clinical pipeline is presented, with a definition of these drugs’ target product profiles and an assessment of the potential role of nanotechnology in their development. Opinions extracted from interviews with experts in the fields of nanomedicine, clinical malaria, and the economic landscape of the disease are included to offer a wider scope of the current requirements to win the fight against malaria and of how nanoscience can contribute to achieve them. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

JTD Keywords: antibody-bearing liposomes, antimalarial drugs, combination therapies, drug-delivery strategies, malaria diagnosis, malaria prophylaxis, malaria therapy, nanocarriers, nanomedicine, nanoparticles, nanotechnology, plasmodium, plasmodium-falciparum, red-blood-cells, targeted delivery, targeted drug delivery, vitro antimalarial activity, Antimalarial drugs, Isothermal amplification lamp, Malaria diagnosis, Malaria prophylaxis, Malaria therapy, Nanocarriers, Nanomedicine, Nanotechnology, Plasmodium, Targeted drug delivery

Le Roux, Anabel-Lise, Tozzi, Caterina, Walani, Nikhil, Quiroga, Xarxa, Zalvidea, Dobryna, Trepat, Xavier, Staykova, Margarita, Arroyo, Marino, Roca-Cusachs, Pere, (2021). Dynamic mechanochemical feedback between curved membranes and BAR protein self-organization Nature Communications 12, 6550

In many physiological situations, BAR proteins reshape membranes with pre-existing curvature (templates), contributing to essential cellular processes. However, the mechanism and the biological implications of this reshaping process remain unclear. Here we show, both experimentally and through modelling, that BAR proteins reshape low curvature membrane templates through a mechanochemical phase transition. This phenomenon depends on initial template shape and involves the co-existence and progressive transition between distinct local states in terms of molecular organization (protein arrangement and density) and membrane shape (template size and spherical versus cylindrical curvature). Further, we demonstrate in cells that this phenomenon enables a mechanotransduction mode, in which cellular stretch leads to the mechanical formation of membrane templates, which are then reshaped into tubules by BAR proteins. Our results demonstrate the interplay between membrane mechanics and BAR protein molecular organization, integrating curvature sensing and generation in a comprehensive framework with implications for cell mechanical responses.

JTD Keywords: aggregation, amphiphysin, domains, vesicles, Article, Cell, Cell component, Curvature, Detection method, Geomembrane, Mechanotransduction, Membrane, Molecular analysis, Phase transition, Physiology, Protein, Self organization

Pérez-Rafael S, Ivanova K, Stefanov I, Puiggalí J, del Valle LJ, Todorova K, Dimitrov P, Hinojosa-Caballero D, Tzanov T, (2021). Nanoparticle-driven self-assembling injectable hydrogels provide a multi-factorial approach for chronic wound treatment Acta Biomaterialia 134, 131-143

Chronic wounds represent a major health burden and drain on medical system. Efficient wound repair is only possible if the dressing materials target simultaneously multiple factors involved in wound chronicity, such as deleterious proteolytic and oxidative enzymes and high bacterial load. Here we develop multifunctional hydrogels for chronic wound management through self-assembling of thiolated hyaluronic acid (HA-SH) and bioactive silver-lignin nanoparticles (Ag@Lig NPs). Dynamic and reversible interactions between the polymer and Ag@Lig NPs yield hybrid nanocomposite hydrogels with shear-thinning and self-healing properties, coupled to zero-order kinetics release of antimicrobial silver in response to infection-related hyalurodinase. The hydrogels inhibit the major enzymes myeloperoxidase and matrix metalloproteinases responsible for wound chronicity in a patient's wound exudate. Furthermore, the lignin-capped AgNPs provide the hydrogel with antioxidant properties and strong antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa. The nanocomposite hydrogels are not toxic to human keratinocytes after 7 days of direct contact. Complete tissue remodeling and restoration of skin integrity is demonstrated in vivo in a diabetic mouse model. Hematological analysis reveals lack of wound inflammation due to bacterial infection or toxicity, confirming the potential of HA-SH/Ag@Lig NPs hydrogels for chronic wound management. Statement of significance: Multifunctional hydrogels are promising materials to promote healing of complex wounds. Herein, we report simple and versatile route to prepare biocompatible and multifunctional self-assembled hydrogels for efficient chronic wound treatment utilizing polymer-nanoparticle interactions. Hybrid silver-lignin nanoparticles (Ag@Lig NPs) played both: i) structural role, acting as crosslinking nodes in the hydrogel and endowing it with shear-thinning (ability to flow under applied shear stress) and self-healing properties, and ii) functional role, imparting strong antibacterial and antioxidant activity. Remarkably, the in situ self-assembling of thiolated hyaluronic acid and Ag@Lig NPs yields nanocomposite hydrogels able to simultaneously inhibits the major factors involved in wound chronicity, namely the overexpressed deleterious proteolytic and oxidative enzymes, and high bacterial load.

JTD Keywords: catechol, chronic wounds, dressing materials, inhibition, mechanism, nano-enabled hydrogels, polyphenols, promogran, self-assembling, silver-lignin nanoparticles, systems, tannins, Chronic wounds, Degradation, Dressing materials, Nano-enabled hydrogels, Self-assembling, Silver-lignin nanoparticles, Thiolated hyaluronic acid

Grechuta, K, Costa, JD, Ballester, BR, Verschure, P, (2021). Challenging the Boundaries of the Physical Self: Distal Cues Impact Body Ownership Frontiers In Human Neuroscience 15, 704414

The unique ability to identify one's own body and experience it as one's own is fundamental in goal-oriented behavior and survival. However, the mechanisms underlying the so-called body ownership are yet not fully understood. Evidence based on Rubber Hand Illusion (RHI) paradigms has demonstrated that body ownership is a product of reception and integration of self and externally generated multisensory information, feedforward and feedback processing of sensorimotor signals, and prior knowledge about the body. Crucially, however, these designs commonly involve the processing of proximal modalities while the contribution of distal sensory signals to the experience of ownership remains elusive. Here we propose that, like any robust percept, body ownership depends on the integration and prediction across all sensory modalities, including distal sensory signals pertaining to the environment. To test our hypothesis, we created an embodied goal-oriented Virtual Air Hockey Task, in which participants were to hit a virtual puck into a goal. In two conditions, we manipulated the congruency of distal multisensory cues (auditory and visual) while preserving proximal and action-driven signals entirely predictable. Compared to a fully congruent condition, our results revealed a significant decrease on three dimensions of ownership evaluation when distal signals were incongruent, including the subjective report as well as physiological and kinematic responses to an unexpected threat. Together, these findings support the notion that the way we represent our body is contingent upon all the sensory stimuli, including distal and action-independent signals. The present data extend the current framework of body ownership and may also find applications in rehabilitation scenarios.

JTD Keywords: active perception, body ownership, distal sensory cues, embodied cognition, forward model, Active perception, Adult, Article, Body ownership, Brain, Cortex, Distal sensory cues, Embodied cognition, Feel, Female, Forward model, Hockey, Human, Human experiment, Integration, Male, Models, Neurons, Perception, Peripersonal space, Prediction, Rehabilitation, Rubber hand illusion, Sensory prediction error, Touch

Nyga, Agata, Muñoz, Jose J., Dercksen, Suze, Fornabaio, Giulia, Uroz, Marina, Trepat, Xavier, Baum, Buzz, Matthews, Helen K., Conte, Vito, (2021). Oncogenic RAS instructs morphological transformation of human epithelia via differential tissue mechanics Science Advances 7, eabg6467

Rodríguez-Contreras A, Torres D, Rafik B, Ortiz-Hernandez M, Ginebra MP, Calero JA, Manero JM, Ruperez E, (2021). Bioactivity and antibacterial properties of calcium- and silver-doped coatings on 3D printed titanium scaffolds Surface & Coatings Technology 421

One of the major problems faced by metallic implants is the high probability of bacterial infections, with significant consequences for the patient. In this work, a thermochemical treatment is proposed to obtain silver-doped calcium titanate coatings on the Ti surface to improve the bioactivity of porous 3D-printed Ti structures and simultaneously provide them with antibacterial properties. A complete characterization of the new coating, the study of the ion release and the analysis of its cytotoxicity were carried out together with evaluation of the natural apatite forming in simulated body fluid (SBF). Moreover, the antibacterial properties of the coatings were assessed against Pseudomona aeruginosa and Escherichia coli as gram-negative and Staphylococcus aureus and Staphylococcus epidermidis as gram-positive bacterial strains. Ag ions were integrated into the Ca titanate layer and Ag nanoparticles were formed within the entire 3D Ti surface. Ca and Ag ions were released from both porous and solid samples into the Hanks' solution for 48 h. The treated surfaces showed no cytotoxicity and an apatite layer precipitated on the entire porous surface when the samples were immersed in SBF. The release of Ag from the surface had a strong antibacterial effect and prevented bacterial adhesion and proliferation on the surface. Moreover, the nanostructured topography of the coating resulted also in a reduction of bacterial adhesion and proliferation, even in absence of Ag. In conclusion, the cost-effective approach here reported provided protection against the most predominant bacterial colonizers to the Ti porous implants, while maintaining their bioactivity.

JTD Keywords: 3d-printing, alkaline, antibacterial activity, arthroplasty, bacterial adhesion, biomaterials, generation, ions, nanoparticles, osseointegration, silver, surface-layer, titanium implants, toxicity, 3d-printing, Antibacterial activity, Biomaterials, Porous structures, Silver, Ti metal, Titanium implants

Puiggalí-Jou A, Babeli I, Roa JJ, Zoppe JO, Garcia-Amorós J, Ginebra MP, Alemán C, Garciá-Torres J, (2021). Remote Spatiotemporal Control of a Magnetic and Electroconductive Hydrogel Network via Magnetic Fields for Soft Electronic Applications Acs Applied Materials & Interfaces 13, 42486-42501

Multifunctional hydrogels are a class of materials offering new opportunities for interfacing living organisms with machines due to their mechanical compliance, biocompatibility, and capacity to be triggered by external stimuli. Here, we report a dual magnetic- and electric-stimuli-responsive hydrogel with the capacity to be disassembled and reassembled up to three times through reversible cross-links. This allows its use as an electronic device (e.g., temperature sensor) in the cross-linked state and spatiotemporal control through narrow channels in the disassembled state via the application of magnetic fields, followed by reassembly. The hydrogel consists of an interpenetrated polymer network of alginate (Alg) and poly(3,4-ethylenedioxythiophene) (PEDOT), which imparts mechanical and electrical properties, respectively. In addition, the incorporation of magnetite nanoparticles (Fe3O4 NPs) endows the hydrogel with magnetic properties. After structural, (electro)chemical, and physical characterization, we successfully performed dynamic and continuous transport of the hydrogel through disassembly, transporting the polymer-Fe3O4 NP aggregates toward a target using magnetic fields and its final reassembly to recover the multifunctional hydrogel in the cross-linked state. We also successfully tested the PEDOT/Alg/Fe3O4 NP hydrogel for temperature sensing and magnetic hyperthermia after various disassembly/re-cross-linking cycles. The present methodology can pave the way to a new generation of soft electronic devices with the capacity to be remotely transported.

JTD Keywords: conductive hydrogel, constructs, magnetic field, magnetite nanoparticle, nanoindentation, soft electronics, spatiotemporal control, Conductive hydrogel, Conductive hydrogels, Magnetic field, Magnetite nanoparticle, Soft electronics, Spatiotemporal control

Abramov A, Maiti B, Keridou I, Puiggalí J, Reiser O, Díaz DD, (2021). A pH-Triggered Polymer Degradation or Drug Delivery System by Light-Mediated Cis/Trans Isomerization of o-Hydroxy Cinnamates Macromolecular Rapid Communications 42, 2100213

A new methodology for the pH-triggered degradation of polymers or for the release of drugs under visible light irradiation based on the cyclization of ortho-hydroxy-cinnamates (oHC) to coumarins is described. The key oHC structural motif can be readily incorporated into the rational design of novel photocleavable polymers via click chemistry. This main-chain moiety undergoes a fast photocleavage when irradiated with 455 nm light provided that a suitable base is added. A series of polyethylene glycol-alt-ortho-hydroxy cinnamate (polyethylene glycol (PEG)(n)-alt-oHC)-based polymers are synthesized and the time-dependent visible-light initiated cleavage of the photoactive monomer and polymer is investigated in solution by a variety of spectroscopic and chromatographic techniques. The photo-degradation behavior of the water-soluble poly(PEG(2000)-alt-oHC) is investigated within a broad pH range (pH = 2.1-11.8), demonstrating fast degradation at pH 11.8, while the stability of the polymer is greatly enhanced at pH 2.1. Moreover, the neat polymer shows long-term stability under daylight conditions, thus allowing its storage without special precautions. In addition, two water-soluble PEG-based drug-carrier molecules (mPEG(2000)-oHC-benzhydrol/phenol) are synthesized and used for drug delivery studies, monitoring the process by UV-vis spectroscopy in an ON/OFF intermittent manner.

JTD Keywords: coumarins, drug delivery, e/z-double bond isomerization, o-hydroxy cinnamates, polymer degradation, Aliphatic compounds, Antioxidant activity, Antitumor, Chromatographic techniques, Chromatography, Cis/trans isomerization, Controlled drug delivery, Coumarin derivatives, Coumarins, Drug delivery, Drug delivery system, E/z-double bond isomerization, Films, Hydrogels, Image enhancement, Light, Long term stability, O-hydroxy cinnamates, Particles, Photoactive monomers, Photodegradation, Polyethylene glycols, Polyethylenes, Polymer degradation, Responsive polymers, Salts, Structural motifs, Synthesis (chemical), Targeted drug delivery, Visible light photocatalysis, Visible-light irradiation

Andrian T, Delcanale P, Pujals S, Albertazzi L, (2021). Correlating Super-Resolution Microscopy and Transmission Electron Microscopy Reveals Multiparametric Heterogeneity in Nanoparticles Nano Letters 21, 5360-5368

The functionalization of nanoparticles with functional moieties is a key strategy to achieve cell targeting in nanomedicine. The interplay between size and ligand number is crucial for the formulation performance and needs to be properly characterized to understand nanoparticle structure-activity relations. However, there is a lack of methods able to measure both size and ligand number at the same time and at the single particle level. Here, we address this issue by introducing a correlative light and electron microscopy (CLEM) method combining super-resolution microscopy (SRM) and transmission electron microscopy (TEM) imaging. We apply our super-resCLEM method to characterize the relationship between size and ligand number and density in PLGA-PEG nanoparticles. We highlight how heterogeneity found in size can impact ligand distribution and how a significant part of the nanoparticle population goes completely undetected in the single-technique analysis. Super-resCLEM holds great promise for the multiparametric analysis of other parameters and nanomaterials.

JTD Keywords: cellular uptake, correlative light and electron microscopy (clem), density, electron microscopy (em), functionalization, heterogeneity, nanomedicine, nanoparticles, pegylation, plga, progress, quantification, size, Correlative light and electron microscopy (clem), Electron microscopy (em), Heterogeneity, Nanomedicine, Nanoparticles, Physicochemical characterization, Super-resolution microscopy (srm)

Mares AG, Pacassoni G, Samitier J, Pujals S, Albertazzi L, (2021). Formulation of tunable size PLGA-PEG nanoparticles for drug delivery using microfluidic technology Plos One 16, e0251821

Amphiphilic block co-polymer nanoparticles are interesting candidates for drug delivery as a result of their unique properties such as the size, modularity, biocompatibility and drug loading capacity. They can be rapidly formulated in a nanoprecipitation process based on self-assembly, resulting in kinetically locked nanostructures. The control over this step allows us to obtain nanoparticles with tailor-made properties without modification of the co-polymer building blocks. Furthermore, a reproducible and controlled formulation supports better predictability of a batch effectiveness in preclinical tests. Herein, we compared the formulation of PLGA-PEG nanoparticles using the typical manual bulk mixing and a microfluidic chip-assisted nanoprecipitation. The particle size tunability and controllability in a hydrodynamic flow focusing device was demonstrated to be greater than in the manual dropwise addition method. We also analyzed particle size and encapsulation of fluorescent compounds, using the common bulk analysis and advanced microscopy techniques: Transmission Electron Microscopy and Total Internal Reflection Microscopy, to reveal the heterogeneities occurred in the formulated nanoparticles. Finally, we performed in vitro evaluation of obtained NPs using MCF-7 cell line. Our results show how the microfluidic formulation improves the fine control over the resulting nanoparticles, without compromising any appealing property of PLGA nanoparticle. The combination of microfluidic formulation with advanced analysis methods, looking at the single particle level, can improve the understanding of the NP properties, heterogeneities and performance.

JTD Keywords: controlled-release, doxorubicin, encapsulation, functional nanoparticles, nanoprecipitation, pharmacokinetics, polymeric nanoparticles, shape, surface-chemistry, In-vitro

Blanco-Fernandez, B, Castano, O, Mateos-Timoneda, MA, Engel, E, Perez-Amodio, S, (2021). Nanotechnology Approaches in Chronic Wound Healing Advances In Wound Care 10, 234-256

Significance: The incidence of chronic wounds is increasing due to our aging population and the augment of people afflicted with diabetes. With the extended knowledge on the biological mechanisms underlying these diseases, there is a novel influx of medical technologies into the conventional wound care market. Recent Advances: Several nanotechnologies have been developed demonstrating unique characteristics that address specific problems related to wound repair mechanisms. In this review, we focus on the most recently developed nanotechnology-based therapeutic agents and evaluate the efficacy of each treatment in in vivo diabetic models of chronic wound healing. Critical Issues: Despite the development of potential biomaterials and nanotechnology-based applications for wound healing, this scientific knowledge is not translated into an increase of commercially available wound healing products containing nanomaterials. Future Directions: Further studies are critical to provide insights into how scientific evidences from nanotechnology-based therapies can be applied in the clinical setting.

JTD Keywords: chronic, diabetes, liposomes, nanofibers, nanoparticles, Chronic, Chronic wound, Diabetes, Diabetic wound, Diabetic-rats, Dressings, Drug mechanism, Extracellular-matrix, Growth-factor, Human, In-vitro, Liposome, Liposomes, Mesenchymal stem-cells, Metal nanoparticle, Nanofiber, Nanofibers, Nanofibrous scaffolds, Nanoparticles, Nanotechnology, Nonhuman, Polyester, Polymer, Polysaccharide, Priority journal, Protein, Review, Self assembled protein nanoparticle, Silk fibroin, Skin wounds, Wound healing, Wound healing promoting agent

Apriceno A, Silvestro I, Girelli A, Francolini I, Pietrelli L, Piozzi A, (2021). Preparation and characterization of chitosan-coated manganese-ferrite nanoparticles conjugated with laccase for environmental bioremediation Polymers 13,

Bioremediation with immobilized enzymes has several advantages, such as the enhancement of selectivity, activity, and stability of biocatalysts, as well as enzyme reusability. Laccase has proven to be a good candidate for the removal of a wide range of contaminants. In this study, naked or modified MnFe O magnetic nanoparticles (MNPs) were used as supports for the immobilization of laccase from Trametes versicolor. To increase enzyme loading and stability, MNPs were coated with chitosan both after the MNP synthesis (MNPs-CS) and during their formation (MNPs-CS ). SEM analysis showed different sizes for the two coated systems, 20 nm and 10 nm for MNPs-CS and MNPs-CS , respectively. After covalent immobilization of laccase by glutaraldehyde, the MNPs-CS -lac and MNPs-CS-lac systems showed a good resistance to temperature denaturation and storage stability. The most promising system for use in repeated batches was MNPs-CS -lac, which degraded about 80% of diclofenac compared to 70% of the free enzyme. The obtained results demonstrated that the MnFe O -CS system could be an excellent candidate for the removal of contaminants. 2 4 in situ in situ in situ in situ 2 4 in situ

JTD Keywords: bioremediation, chitosan, diclofenac, diclofenac removal, immobilized enzyme, laccase, magnetic nanoparticles, phase, removal, supports, Bioremediation, Chitosan, Diclofenac removal, Enzyme immobilization, Immobilized enzyme, Laccase, Magnetic nanoparticles

Magdanz V, Vivaldi J, Mohanty S, Klingner A, Vendittelli M, Simmchen J, Misra S, Khalil ISM, (2021). Impact of Segmented Magnetization on the Flagellar Propulsion of Sperm-Templated Microrobots Advanced Science 8, 2004037

© 2021 The Authors. Advanced Science published by Wiley-VCH GmbH Technical design features for improving the way a passive elastic filament produces propulsive thrust can be understood by analyzing the deformation of sperm-templated microrobots with segmented magnetization. Magnetic nanoparticles are electrostatically self-assembled on bovine sperm cells with nonuniform surface charge, producing different categories of sperm-templated microrobots. Depending on the amount and location of the nanoparticles on each cellular segment, magnetoelastic and viscous forces determine the wave pattern of each category during flagellar motion. Passively propagating waves are induced along the length of these microrobots using external rotating magnetic fields and the resultant wave patterns are measured. The response of the microrobots to the external field reveals distinct flow fields, propulsive thrust, and frequency responses during flagellar propulsion. This work allows predictions for optimizing the design and propulsion of flexible magnetic microrobots with segmented magnetization.

JTD Keywords: biohybrid microrobots, flagellar propulsion, magnetic actuation, nanoparticles, sperm cells, Biohybrid microrobots, Flagellar propulsion, Magnetic actuation, Nanoparticles, Sperm cells

Hortelao AC, Simó C, Guix M, Guallar-Garrido S, Julián E, Vilela D, Rejc L, Ramos-Cabrer P, Cossío U, Gómez-Vallejo V, Patiño T, Llop J, Sánchez S, (2021). Swarming behavior and in vivo monitoring of enzymatic nanomotors within the bladder Science Robotics 6, eabd2823

Enzyme-powered nanomotors are an exciting technology for biomedical applications due to their ability to navigate within biological environments using endogenous fuels. However, limited studies into their collective behavior and demonstrations of tracking enzyme nanomotors in vivo have hindered progress toward their clinical translation. Here, we report the swarming behavior of urease-powered nanomotors and its tracking using positron emission tomography (PET), both in vitro and in vivo. For that, mesoporous silica nanoparticles containing urease enzymes and gold nanoparticles were used as nanomotors. To image them, nanomotors were radiolabeled with either I on gold nanoparticles or F-labeled prosthetic group to urease. In vitro experiments showed enhanced fluid mixing and collective migration of nanomotors, demonstrating higher capability to swim across complex paths inside microfabricated phantoms, compared with inactive nanomotors. In vivo intravenous administration in mice confirmed their biocompatibility at the administered dose and the suitability of PET to quantitatively track nanomotors in vivo. Furthermore, nanomotors were administered directly into the bladder of mice by intravesical injection. When injected with the fuel, urea, a homogeneous distribution was observed even after the entrance of fresh urine. By contrast, control experiments using nonmotile nanomotors (i.e., without fuel or without urease) resulted in sustained phase separation, indicating that the nanomotors’ self-propulsion promotes convection and mixing in living reservoirs. Active collective dynamics, together with the medical imaging tracking, constitute a key milestone and a step forward in the field of biomedical nanorobotics, paving the way toward their use in theranostic applications. 124 18

JTD Keywords: cell, reversal, silica nanoparticles, size, step, transport, Propelled micromotors

Moya-Andérico L, Vukomanovic M, Cendra MdM, Segura-Feliu M, Gil V, del Río JA, Torrents E, (2021). Utility of Galleria mellonella larvae for evaluating nanoparticle toxicology Chemosphere 266, 129235

© 2020 Elsevier Ltd The use of nanoparticles in consumer products is currently on the rise, so it is important to have reliable methods to predict any associated toxicity effects. Traditional in vitro assays fail to mimic true physiological responses of living organisms against nanoparticles whereas murine in vivo models are costly and ethically controversial. For these reasons, this study aimed to evaluate the efficacy of Galleria mellonella as an alternative, non-rodent in vivo model for examining nanoparticle toxicity. Silver, selenium, and functionalized gold nanoparticles were synthesized, and their toxicity was assessed in G. mellonella larvae. The degree of acute toxicity effects caused by each type of NP was efficiently detected by an array of indicators within the larvae: LD50 calculation, hemocyte proliferation, NP distribution, behavioral changes, and histological alterations. G. mellonella larvae are proposed as a nanotoxicological model that can be used as a bridge between in vitro and in vivo murine assays in order to obtain better predictions of NP toxicity.

JTD Keywords: cellular uptake, cytotoxicity, galleria mellonella, gold nanoparticles, hemocytes, nanoparticles, nanotoxicity, non-rodent in vivo model, non-rodent in vivo model, oxidative stress, selenium-compounds, silica nanoparticles, silver nanoparticles, toxicity, toxicity screening, vitro, Galleria mellonella, Hemocytes, In-vivo model, Nanoparticles, Nanotoxicity, Non-rodent in vivo model, Toxicity screening

Estrada-Petrocelli L, Torres A, Sarlabous L, Rafols-De-Urquia M, Ye-Lin Y, Prats-Boluda G, Jane R, Garcia-Casado J, (2021). Evaluation of Respiratory Muscle Activity by Means of Concentric Ring Electrodes Ieee Transactions On Biomedical Engineering 68, 1005-1014

© 1964-2012 IEEE. Surface electromyography (sEMG) can be used for the evaluation of respiratory muscle activity. Recording sEMG involves the use of surface electrodes in a bipolar configuration. However, electrocardiographic (ECG) interference and electrode orientation represent considerable drawbacks to bipolar acquisition. As an alternative, concentric ring electrodes (CREs) can be used for sEMG acquisition and offer great potential for the evaluation of respiratory muscle activity due to their enhanced spatial resolution and simple placement protocol, which does not depend on muscle fiber orientation. The aim of this work was to analyze the performance of CREs during respiratory sEMG acquisitions. Respiratory muscle sEMG was applied to the diaphragm and sternocleidomastoid muscles using a bipolar and a CRE configuration. Thirty-two subjects underwent four inspiratory load spontaneous breathing tests which was repeated after interchanging the electrode positions. We calculated parameters such as (1) spectral power and (2) median frequency during inspiration, and power ratios of inspiratory sEMG without ECG in relation to (3) basal sEMG without ECG (Rins/noise), (4) basal sEMG with ECG (Rins/cardio) and (5) expiratory sEMG without ECG (Rins/exp). Spectral power, Rins/noise and Rins/cardio increased with the inspiratory load. Significantly higher values (p < 0.05) of Rins/cardio and significantly higher median frequencies were obtained for CREs. Rins/noise and Rins/exp were higher for the bipolar configuration only in diaphragm sEMG recordings, whereas no significant differences were found in the sternocleidomastoid recordings. Our results suggest that the evaluation of respiratory muscle activity by means of sEMG can benefit from the remarkably reduced influence of cardiac activity, the enhanced detection of the shift in frequency content and the axial isotropy of CREs which facilitates its placement.

JTD Keywords: atmospheric measurements, concentric ring electrodes, electrocardiography, electrodes, electromyography, laplacian potential, non-invasive respiratory monitoring, particle measurements, respiratory muscles, surface electromyography, Concentric ring electrodes, Laplacian potential, Muscles, Non-invasive respiratory monitoring, Respiratory muscles, Surface electromyography

Puiggalí-Jou A, Wedepohl S, Theune LE, Alemán C, Calderón M, (2021). Effect of conducting/thermoresponsive polymer ratio on multitasking nanogels Materials Science & Engineering C-Materials For Biological Applications 119, 111598

© 2020 Elsevier B.V. Semi-interpenetrated nanogels (NGs) able to release and sense diclofenac (DIC) have been designed to act as photothermal agents with the possibility to ablate cancer cells using mild-temperatures (<45 °C). Combining mild heat treatments with simultaneous chemotherapy appears as a very promising therapeutic strategy to avoid heat resistance or damaging the surrounding tissues. Particularly, NGs consisted on a poly(N-isopropylacrylamide) (PNIPAM) and dendritic polyglycerol (dPG) mesh containing a semi-interpenetrating network (SIPN) of poly(hydroxymethyl 3,4-ethylenedioxythiophene) (PHMeEDOT). The PHMeEDOT acted as photothermal and conducting agent, while PNIPAM-dPG NG provided thermoresponsivity and acted as stabilizer. We studied how semi-interpenetration modified the physicochemical characteristics of the thermoresponsive SIPN NGs and selected the best condition to generate a multifunctional photothermal agent. The thermoswitchable conductiveness of the multifunctional NGs and the redox activity of DIC could be utilized for its electrochemical detection. Besides, as proof of the therapeutic concept, we investigated the combinatorial effect of photothermal therapy (PTT) and DIC treatment using the HeLa cancer cell line in vitro. Within 15 min NIR irradiation without surpassing 45 °C we were able to kill 95% of the cells, demonstrating the potential of SIPN NGs as drug carriers, sensors and agents for mild PTT.

JTD Keywords: cells, cellulose, conducting polymers, controlled delivery, diclofenac, efficiency, electrochemical oxidation, electrochemical sensors, nanogels, nanoparticles, photothermal therapy, pnipam, poly(3,4-ethylenedioxythiophene), Conducting polymers, Electrochemical sensors, Nanogels, Photothermal therapy

Woythe L, Tito NB, Albertazzi L, (2021). A quantitative view on multivalent nanomedicine targeting Advanced Drug Delivery Reviews 169, 1-21

© 2020 The Authors Although the concept of selective delivery has been postulated over 100 years ago, no targeted nanomedicine has been clinically approved so far. Nanoparticles modified with targeting ligands to promote the selective delivery of therapeutics towards a specific cell population have been extensively reported. However, the rational design of selective particles is still challenging. One of the main reasons for this is the lack of quantitative theoretical and experimental understanding of the interactions involved in cell targeting. In this review, we discuss new theoretical models and experimental methods that provide a quantitative view of targeting. We show the new advancements in multivalency theory enabling the rational design of super-selective nanoparticles. Furthermore, we present the innovative approaches to obtain key targeting parameters at the single-cell and single molecule level and their role in the design of targeting nanoparticles. We believe that the combination of new theoretical multivalent design and experimental methods to quantify receptors and ligands aids in the rational design and clinical translation of targeted nanomedicines.

JTD Keywords: binding-kinetics, biological identity, biomolecular corona, blood-brain-barrier, drug-delivery, gold nanoparticles, multivalency, nanotechnology, protein corona, quantitative characterization, rational design, super-selectivity, superresolution microscopy, tumor heterogeneity, Ligand-receptor interactions, Multivalency, Nanotechnology, Quantitative characterization, Rational design, Super-selectivity

Feiner-Gracia N, Glinkowska Mares A, Buzhor M, Rodriguez-Trujillo R, Samitier Marti J, Amir RJ, Pujals S, Albertazzi L, (2021). Real-Time Ratiometric Imaging of Micelles Assembly State in a Microfluidic Cancer-on-a-Chip Acs Applied Bio Materials 4, 669-681

© 2020 American Chemical Society. The performance of supramolecular nanocarriers as drug delivery systems depends on their stability in the complex and dynamic biological media. After administration, nanocarriers are challenged by physiological barriers such as shear stress and proteins present in blood, endothelial wall, extracellular matrix, and eventually cancer cell membrane. While early disassembly will result in a premature drug release, extreme stability of the nanocarriers can lead to poor drug release and low efficiency. Therefore, comprehensive understanding of the stability and assembly state of supramolecular carriers in each stage of delivery is the key factor for the rational design of these systems. One of the main challenges is that current 2D in vitro models do not provide exhaustive information, as they fail to recapitulate the 3D tumor microenvironment. This deficiency in the 2D model complexity is the main reason for the differences observed in vivo when testing the performance of supramolecular nanocarriers. Herein, we present a real-time monitoring study of self-assembled micelles stability and extravasation, combining spectral confocal microscopy and a microfluidic cancer-on-a-chip. The combination of advanced imaging and a reliable 3D model allows tracking of micelle disassembly by following the spectral properties of the amphiphiles in space and time during the crucial steps of drug delivery. The spectrally active micelles were introduced under flow and their position and conformation continuously followed by spectral imaging during the crossing of barriers, revealing the interplay between carrier structure, micellar stability, and extravasation. Integrating the ability of the micelles to change their fluorescent properties when disassembled, spectral confocal imaging and 3D microfluidic tumor blood vessel-on-a-chip resulted in the establishment of a robust testing platform suitable for real-time imaging and evaluation of supramolecular drug delivery carrier's stability.

JTD Keywords: cancer-on-a-chip, complex, delivery, endothelial-cells, in-vitro, microfluidic, model, nanoparticle, penetration, shear-stress, stability, supramolecular, Cancer-on-a-chip, Cell-culture, Micelle, Microfluidic, Nanoparticle, Stability, Supramolecular

Watt, AC, Cejas, P, DeCristo, MJ, Metzger, O, Lam, EYN, Qiu, XT, BrinJones, H, Kesten, N, Coulson, R, Font-Tello, A, Lim, K, Vadhi, R, Daniels, VW, Montero, J, Taing, L, Meyer, CA, Gilan, O, Bell, CC, Korthauer, KD, Giambartolomei, C, Pasaniuc, B, Seo, JH, Freedman, ML, Ma, CT, Ellis, MJ, Krop, I, Winer, E, Letai, A, Brown, M, Dawson, MA, Long, HW, Zhao, JJ, Goel, S, (2021). CDK4/6 inhibition reprograms the breast cancer enhancer landscape by stimulating AP-1 transcriptional activity Nature Cancer 2, 34-48

Goel and colleagues show that CDK4/6 inhibition induces global chromatin changes mediated by AP-1 factors, which mediate key biological and clinical effects in breast cancer. Pharmacologic inhibitors of cyclin-dependent kinases 4 and 6 (CDK4/6) were designed to induce cancer cell cycle arrest. Recent studies have suggested that these agents also exert other effects, influencing cancer cell immunogenicity, apoptotic responses and differentiation. Using cell-based and mouse models of breast cancer together with clinical specimens, we show that CDK4/6 inhibitors induce remodeling of cancer cell chromatin characterized by widespread enhancer activation, and that this explains many of these effects. The newly activated enhancers include classical super-enhancers that drive luminal differentiation and apoptotic evasion, as well as a set of enhancers overlying endogenous retroviral elements that are enriched for proximity to interferon-driven genes. Mechanistically, CDK4/6 inhibition increases the level of several activator protein-1 transcription factor proteins, which are in turn implicated in the activity of many of the new enhancers. Our findings offer insights into CDK4/6 pathway biology and should inform the future development of CDK4/6 inhibitors.

JTD Keywords: Abemaciclib, Androgen receptor, Animal experiment, Animal model, Animal tissue, Apoptosis, Article, Breast cancer, C-jun, Cancer cell, Carcinoembryonic antigen related cell adhesion molecule 1, Caspase 3, Cell cycle arrest, Cells, Chromatin, Chromatin immunoprecipitation, Controlled study, Cyclin dependent kinase 4, Cyclin dependent kinase 6, Dna damage, Epidermal growth factor receptor 2, Estrogen receptor, Female, Flow cytometry, Fulvestrant, Hla drb1 antigen, Human, Human cell, Immunoblotting, Immunogenicity, Immunoprecipitation, Interferon, Luciferase assay, Mcf-7 cell line, Mda-mb-231 cell line, Microarray analysis, Morphogenesis, Mouse, Nonhuman, Palbociclib, Protein, Protein expression, Rb, Resistance, Rna polymerase ii, Rna sequence, Selective-inhibition, Senescence, Short tandem repeat, Signal transduction, Tamoxifen, Transcription elongation, Transcription factor, Transcription factor ap 1, Transcriptome, Tumor biopsy, Tumor differentiation, Tumor spheroid, Tumor xenograft, Vinculin, Whole exome sequencing

Marti, D, Martin-Martinez, E, Torras, J, Bertran, O, Turon, P, Aleman, C, (2021). In silico antibody engineering for SARS-CoV-2 detection Computational And Structural Biotechnology Journal 19, 5525-5534

Engineered immunoglobulin-G molecules (IgGs) are of wide interest for the development of detection elements in protein-based biosensors with clinical applications. The strategy usually employed for the de novo design of such engineered IgGs consists on merging fragments of the three-dimensional structure of a native IgG, which is immobilized on the biosensor surface, and of an antibody with an exquisite target specificity and affinity. In this work conventional and accelerated classical molecular dynamics (cMD and aMD, respectively) simulations have been used to propose two IgG-like antibodies for COVID-19 detection. More specifically, the crystal structure of the IgG1 B12 antibody, which inactivates the human immunodeficiency virus-1, has been merged with the structure of the antibody CR3022 Fab tightly bounded to SARS-CoV-2 receptor-binding domain (RBD) and the structure of the 5309 antibody Fab fragment complexed with SARS-CoV-2 RBD. The two constructed antibodies, named IgG1-CR3022 and IgG1-S309, respectively, have been immobilized on a stable gold surface through a linker. Analyses of the influence of both the merging strategy and the substrate on the stability of the two constructs indicate that the IgG1-S309 antibody better preserves the neutralizing structure than the IgG1-CR3022 one. Overall, results indicate that the IgG1-S309 is appropriated for the generation of antibody based sensors for COVID-19 diagnosis. (C) 2021 The Author(s). Published by Elsevier B.V. on behalf of Research Network of Computational and Structural Biotechnology.

JTD Keywords: cr3022, igg1, molecular engineering, s309, Antibodies, Antibody engineering, Biosensors, Chemical detection, Clinical application, Cov, Cr3022, Crystal structure, Design, Diseases, Gold nanoparticles, Igg1, Igg1 antibody, Immobilization, Immunoglobulin g, Immunosensor, In-silico, Merging, Molecular dynamics, Molecular engineering, Orientation, Protein-based biosensors, Receptor-binding domains, S309, Sars, Sensor, Spike protein, Target, Vaccine, Viruses

Sola-Barrado, B., M. Leite, D., Scarpa, E., Duro-Castano, A., Battaglia, G., (2020). Combinatorial intracellular delivery screening of anticancer drugs Molecular Pharmaceutics 17, (12), 4709-4714

Conventional drug solubilization strategies limit the understanding of the full potential of poorly water-soluble drugs during drug screening. Here, we propose a screening approach in which poorly water-soluble drugs are entrapped in poly(2-(methacryloyloxyethyl phosphorylcholine)-poly(2-(diisopropylaminoethyl methacryate) (PMPC-PDPA) polymersomes (POs) to enhance drug solubility and facilitate intracellular delivery. By using a human pediatric glioma cell model, we demonstrated that PMPC-PDPA POs mediated intracellular delivery of cytotoxic and epigenetic drugs by receptor-mediated endocytosis. Additionally, when delivered in combination, drug-loaded PMPC-PDPA POs triggered both an enhanced drug efficacy and synergy compared to that of a conventional combinatorial screening. Hence, our comprehensive synergy analysis illustrates that our screening methodology, in which PMPC-PDPA POs are used for intracellular codelivery of drugs, allows us to identify potent synergistic profiles of anticancer drugs.

JTD Keywords: Combination therapy, Drug screening, Drug solubilization, Intracellular drug delivery, Polymeric nanoparticles, Synergy analysis

Delcanale, P., Albertazzi, L., (2020). DNA-PAINT super-resolution imaging data of surface exposed active sites on particles Data in Brief 30, 105468

Surface functionalization with targeting ligands confers to nanomaterials the ability of selectively recognize a biological target. Therefore, a quantitative characterization of surface functional molecules is critical for the rational development of nanomaterials-based applications, especially in nanomedicine research. Single-molecule localization microscopy can provide visualization of surface molecules at the level of individual particles, preserving the integrity of the material and overcoming the limitations of analytical methods based on ensemble averaging. Here we provide single-molecule localization data obtained on streptavidin-coated polystyrene particles, which can be exploited as a model system for surface-functionalized materials. After loading of the active sites of streptavidin molecules with a biotin-conjugated probe, they were imaged with a DNA-PAINT imaging approach, which can provide single-molecule imaging at subdiffraction resolution and molecule counting. Both raw records and analysed data, consisting in a list of space-time single-molecule coordinates, are shared. Additionally, Matlab functions are provided that analyse the single-molecule coordinates in order to quantify features of individual particles. These data might constitute a valuable reference for applications of similar quantitative imaging methodologies to other types of functionalized nanomaterials.

JTD Keywords: DNA-PAINT, Functional materials, Nanoparticles, Single-molecule localization microscopy, Super-resolution microscopy

Alert, R., Trepat, X., (2020). Physical models of collective cell migration Annual Review of Condensed Matter Physics 11, 77-101

Collective cell migration is a key driver of embryonic development, wound healing, and some types of cancer invasion. Here, we provide a physical perspective of the mechanisms underlying collective cell migration. We begin with a catalog of the cell-cell and cell-substrate interactions that govern cell migration, which we classify into positional and orientational interactions. We then review the physical models that have been developed to explain how these interactions give rise to collective cellular movement. These models span the subcellular to the supracellular scales, and they include lattice models, phase-field models, active network models, particle models, and continuum models. For each type of model, we discuss its formulation, its limitations, and the main emergent phenomena that it has successfully explained. These phenomena include flocking and fluid-solid transitions, as well as wetting, fingering, and mechanical waves in spreading epithelial monolayers. We close by outlining remaining challenges and future directions in the physics of collective cell migration.

JTD Keywords: Active network models, Cellular Potts models, Continuum models, Particle models, Phase-field models, Tissue biophysics

Hernández-Albors, Alejandro, Castaño, Albert G., Fernández-Garibay, Xiomara, Ortega, María Alejandra, Balaguer, Jordina, Ramón-Azcón, Javier, (2019). Microphysiological sensing platform for an in-situ detection of tissue-secreted cytokines Biosensors and Bioelectronics: X 2, 100025

Understanding the protein-secretion dynamics from single, specific tissues is critical toward the advancement of disease detection and treatments. However, such secretion dynamics remain difficult to measure in vivo due to the uncontrolled contributions from other tissue populations. Here, we describe an integrated platform designed for the reliable, near real-time measurements of cytokines secreted from an in vitro single-tissue model. In our setup, we grow 3D biomimetic tissues to discretize cytokine source, and we separate them from a magnetic microbead-based biosensing system using a Transwell insert. This design integrates physiochemically controlled biological activity, high-sensitivity protein detection (LOD < 20 pg mL−1), and rapid protein diffusion to enable non-invasive, near real-time measurements. To showcase the specificity and sensitivity of the system, we use our setup to probe the inflammatory process related to the protein Interleukine 6 (IL-6) and to the Tumor Necrosis Factor (TNF-α). We show that our setup can monitor the time-dependence profile of IL-6 and TNF-α secretion that results from the electrical and chemical stimulation of 3D skeletal muscle tissues. We demonstrate a novel and affordable methodology for discretizing the secretion kinetics of specific tissues for advancing metabolic-disorder studies and drug-screening applications.

JTD Keywords: Microphysiological tissues, Tissue engineering, Electrochemical, biosensors, Magnetic particles, Skeletal muscle, Electric stimulation

Vukomanovic, M., Torrents, E., (2019). High time resolution and high signal-to-noise monitoring of the bacterial growth kinetics in the presence of plasmonic nanoparticles Journal of Nanobiotechnology 17, (1), 21

Background: Emerging concepts for designing innovative drugs (i.e., novel generations of antimicrobials) frequently include nanostructures, new materials, and nanoparticles (NPs). Along with numerous advantages, NPs bring limitations, partly because they can limit the analytical techniques used for their biological and in vivo validation. From that standpoint, designing innovative drug delivery systems requires advancements in the methods used for their testing and investigations. Considering the well-known ability of resazurin-based methods for rapid detection of bacterial metabolisms with very high sensitivity, in this work we report a novel optimization for tracking bacterial growth kinetics in the presence of NPs with specific characteristics, such as specific optical properties. Results: Arginine-functionalized gold composite (HAp/Au/arginine) NPs, used as the NP model for validation of the method, possess plasmonic properties and are characterized by intensive absorption in the UV/vis region with a surface plasmon resonance maximum at 540 nm. Due to the specific optical properties, the NP absorption intensively interferes with the light absorption measured during the evaluation of bacterial growth (optical density; OD600). The results confirm substantial nonspecific interference by NPs in the signal detected during a regular turbidity study used for tracking bacterial growth. Instead, during application of a resazurin-based method (Presto Blue), when a combination of absorption and fluorescence detection is applied, a substantial increase in the signal-to-noise ratio is obtained that leads to the improvement of the accuracy of the measurements as verified in three bacterial strains tested with different growth rates (E. coli, P. aeruginosa, and S. aureus). Conclusions: Here, we described a novel procedure that enables the kinetics of bacterial growth in the presence of NPs to be followed with high time resolution, high sensitivity, and without sampling during the kinetic study. We showed the applicability of the Presto Blue method for the case of HAp/Au/arginine NPs, which can be extended to various types of metallic NPs with similar characteristics. The method is a very easy, economical, and reliable option for testing NPs designed as novel antimicrobials.

JTD Keywords: Antimicrobial nanoparticles, Arginine-functionalized gold, Bacterial growth kinetics, Plasmonic nanoparticles, Presto Blue

De Matteis, Valeria, Rizzello, Loris, Ingrosso, Chiara, Liatsi-Douvitsa, Eva, De Giorgi, Maria Luisa, De Matteis, Giovanni, Rinaldi, Rosaria, (2019). Cultivar-dependent anticancer and antibacterial properties of silver nanoparticles synthesized using leaves of different Olea Europaea trees Nanomaterials 9, (11), 1544

The green synthesis of nanoparticles (NPs) is currently under worldwide investigation as an eco-friendly alternative to traditional routes (NPs): the absence of toxic solvents and catalysts make it suitable in the design of promising nanomaterials for nanomedicine applications. In this work, we used the extracts collected from leaves of two cultivars (Leccino and Carolea) belonging to the species Olea Europaea, to synthesize silver NPs (AgNPs) in different pH conditions and low temperature. NPs underwent full morphological characterization with the aim to define a suitable protocol to obtain a monodispersed population of AgNPs. Afterwards, to validate the reproducibility of the mentioned synthetic procedure, we moved on to another Mediterranean plant, the Laurus Nobilis. Interestingly, the NPs obtained using the two olive cultivars produced NPs with different shape and size, strictly depending on the cultivar selected and pH. Furthermore, the potential ability to inhibit the growth of two woman cancer cells (breast adenocarcinoma cells, MCF-7 and human cervical epithelioid carcinoma, HeLa) were assessed for these AgNPs, as well as their capability to mitigate the bacteria concentration in samples of contaminated well water. Our results showed that toxicity was stronger when MCF-7 and Hela cells were exposed to AgNPs derived from Carolea obtained at pH 7 presenting irregular shape; on the other hand, greater antibacterial effect was revealed using AgNPs obtained at pH 8 (smaller and monodispersed) on well water, enriched with bacteria and coliforms.

JTD Keywords: Green synthesis, Silver nanoparticles, Olea Europaea, Leccino, Carolea, Cytotoxicity, Genotoxicity, Antibacterial activity

Oliveira, V. R., Uriarte, J. J., Falcones, B., Jorba, I., Zin, W. A., Farré, R., Navajas, D., Almendros, I., (2019). Biomechanical response of lung epithelial cells to iron oxide and titanium dioxide nanoparticles Frontiers in Physiology 10, 1047

Increasing evidence shows that lungs can be damaged by inhalation of nanoparticles (NPs) at environmental and occupational settings. Recent findings have associated the exposure to iron oxide (Fe2O3) and titanium dioxide (TiO2) – NPs widely used in biomedical and clinical research – with pulmonary oxidative stress and inflammation. Although changes on cellular mechanics could contribute to pulmonary inflammation, there is no information regarding the effects of Fe2O3 and TiO2 on alveolar epithelial cell biomechanics. The aim was to investigate the NPs-induced biomechanical effects in terms of cell stiffness and traction forces exerted by human alveolar epithelial cells. Cell Young’s modulus (E) measured by atomic force microscopy in alveolar epithelial cells significantly decreased after exposure to Fe2O3 and TiO2 (-28 and -25%, respectively) compared to control conditions. Moreover, both NPs induced a similar reduction in the traction forces exerted by the alveolar epithelial cells in comparison to the control conditions. Accordingly, immunofluorescence images revealed a reduction of actomyosin stress fibers in response to the exposure to NPs. However, no inflammatory response was detected. In conclusion, an acute exposure of epithelial pulmonary cells to Fe2O3 and TiO2 NPs, which was mild since it was non-cytotoxic and did not induce inflammation, modified cell biomechanical properties which could be translated into damage of the epithelial barrier integrity, suggesting that mild environmental inhalation of Fe2O3 and TiO2 NPs could not be innocuous.

JTD Keywords: Actomyosin fibers, Air pollution, Cell biomechanics, Lung epithelium, Nanoparticles

García-Díaz, María, Birch, Ditlev, Wan, Feng, Mørck Nielsen, Hanne, (2018). The role of mucus as an invisible cloak to transepithelial drug delivery by nanoparticles Advanced Drug Delivery Reviews 124, 107-124

Mucosal administration of drugs and drug delivery systems has gained increasing interest. However, nanoparticles intended to protect and deliver drugs to epithelial surfaces require transport through the surface-lining mucus. Translation from bench to bedside is particularly challenging for mucosal administration since a variety of parameters will influence the specific barrier properties of the mucus including the luminal fluids, the microbiota, the mucus composition and clearance rate, and the condition of the underlying epithelia. Besides, after administration, nanoparticles interact with the mucosal components, forming a biomolecular corona that modulates their behavior and fate after mucosal administration. These interactions are greatly influenced by the nanoparticle properties, and therefore different designs and surface-engineering strategies have been proposed. Overall, it is essential to evaluate these biomolecule-nanoparticle interactions by complementary techniques using complex and relevant mucus barrier matrices.

JTD Keywords: Nanoparticle formulation strategies, Corona formation, Digestive tract, Respiratory tract, Luminal content, Methodologies, Analysis

Katuri, Jaideep, Caballero, David, Voituriez, R., Samitier, Josep, Sanchez, Samuel, (2018). Directed flow of micromotors through alignment interactions with micropatterned ratchets ACS Nano 12, (7), 7282-7291

To achieve control over naturally diffusive, out-of-equilibrium systems composed of self-propelled particles, such as cells or self-phoretic colloids, is a long-standing challenge in active matter physics. The inherently random motion of these active particles can be rectified in the presence of local and periodic asymmetric cues given that a non-trivial interaction exists between the self-propelled particle and the cues. Here, we exploit the phoretic and hydrodynamic interactions of synthetic micromotors with local topographical features to break the time-reversal symmetry of particle trajectories and to direct a macroscopic flow of micromotors. We show that the orientational alignment induced on the micromotors by the topographical features, together with their geometrical asymmetry, are crucial in generating directional particle flow. We also show that our system can be used to concentrate micromotors in confined spaces and identify the interactions responsible for this effect. Finally, we develop a minimal model which identifies the main parameters of the system responsible for the observed rectification. Overall, our system allows for robust control over both temporal and spatial distribution of synthetic micromotors.

JTD Keywords: Active colloids, Directional control, Janus particles, Micromotors, Self-propulsion

Navarro-Requena, Claudia, Weaver, Jessica D., Clark, Amy Y., Clift, Douglas A., Pérez-Amodio, Soledad, Castaño, Óscar, Zhou, Dennis W., García, Andrés J., Engel, Elisabeth, (2018). PEG hydrogel containing calcium-releasing particles and mesenchymal stromal cells promote vessel maturation Acta Biomaterialia 67, 53-65

The use of human mesenchymal stromal cells (hMSC) for treating diseased tissues with poor vascularization has received significant attention, but low cell survival has hampered its translation to the clinic. Bioglasses and glass-ceramics have also been suggested as therapeutic agents for stimulating angiogenesis in soft tissues, but these effects need further evaluation in vivo. In this study, calcium-releasing particles and hMSC were combined within a hydrogel to examine their vasculogenic potential in vitro and in vivo. The particles provided sustained calcium release and showed proangiogenic stimulation in a chorioallantoic membrane (CAM) assay. The number of hMSC encapsulated in a degradable RGD-functionalized PEG hydrogel containing particles remained constant over time and IGF-1 release was increased. When implanted in the epidydimal fat pad of immunocompromised mice, this composite material improved cell survival and stimulated vessel formation and maturation. Thus, the combination of hMSC and calcium-releasing glass-ceramics represents a new strategy to achieve vessel stabilization, a key factor in the revascularization of ischemic tissues. Statement of Significance: Increasing blood vessel formation in diseased tissues with poor vascularization is a current clinical challenge. Cell therapy using human mesenchymal stem cells has received considerable interest, but low cell survival has hampered its translation to the clinic. Bioglasses and glass-ceramics have been explored as therapeutic agents for stimulating angiogenesis in soft tissues, but these effects need further evaluation in vivo. By incorporating both human mesenchymal stem cells and glass-ceramic particles in an implantable hydrogel, this study provides insights into the vasculogenic potential in soft tissues of the combined strategies. Enhancement of vessel formation and maturation supports further investigation of this strategy.

JTD Keywords: Calcium, Glass-ceramic particles, Vascularization, hMSC, Hydrogel

Silva, N., Riveros, A., Yutronic, N., Lang, E., Chornik, B., Guerrero, S., Samitier, J., Jara, P., Kogan, M. J., (2018). Photothermally controlled methotrexate release system using β-cyclodextrin and gold nanoparticles Nanomaterials 8, (12), 985

The inclusion compound (IC) of cyclodextrin (CD) containing the antitumor drug Methotrexate (MTX) as a guest molecule was obtained to increase the solubility of MTX and decrease its inherent toxic effects in nonspecific cells. The IC was conjugated with gold nanoparticles (AuNPs), obtained by a chemical method, creating a ternary intelligent delivery system for MTX molecules, based on the plasmonic properties of the AuNPs. Irradiation of the ternary system, with a laser wavelength tunable with the corresponding surface plasmon of AuNPs, causes local energy dissipation, producing the controlled release of the guest from CD cavities. Finally, cell viability was evaluated using MTS assays for β-CD/MTX and AuNPs + β-CD/MTX samples, with and without irradiation, against HeLa tumor cells. The irradiated sample of the ternary system AuNPs + β-CD/MTX produced a diminution in cell viability attributed to the photothermal release of MTX.

JTD Keywords: Cyclodextrin, Delivery system, Gold nanoparticles, Inclusion compound, Irradiation, Laser, Methotrexate, Photothermal release

Gállego, Isaac, Manning, Brendan, Prades, Joan Daniel, Mir, Mònica, Samitier, Josep, Eritja, Ramon, (2017). DNA-origami-driven lithography for patterning on gold surfaces with sub-10 nm resolution Advanced Materials 29, 1603233

Agusil, Juan Pablo, Torras, Núria, Duch, Marta, Esteve, Jaume, Pérez-García, Lluïsa, Samitier, Josep, Plaza, José A., (2017). Highly anisotropic suspended planar-array chips with multidimensional sub-micrometric biomolecular patterns Advanced Functional Materials 27, 1605912

Suspended planar-array (SPA) chips embody millions of individual miniaturized arrays to work in extremely small volumes. Here, the basis of a robust methodology for the fabrication of SPA silicon chips with on-demand physical and chemical anisotropies is demonstrated. Specifically, physical traits are defined during the fabrication process with special focus on the aspect ratio, branching, faceting, and size gradient of the final chips. Additionally, the chemical attributes augment the functionality of the chips with the inclusion of complete coverage or patterns of selected biomolecules on the surface of the chips with contact printing techniques, offering an extremely high versatility, not only with the choice of the pattern shape and distribution but also in the choice of biomolecular inks to pattern. This approach increases the miniaturization of printed arrays in 3D structures by two orders of magnitude compared to those previously demonstrated. Finally, functional micrometric and sub-micrometric patterned features are demonstrated with an antibody binding assay with the recognition of the printed spots with labeled antibodies from solution. The selective addition of physical and chemical attributes on the suspended chips represents the basis for future biomedical assays performed within extremely small volumes.

JTD Keywords: Microcontact printing, Microparticles, Molecular multiplexing, Polymer pen lithography, Silicon chip technology

Feiner-Gracia, Natalia, Beck, Michaela, Pujals, Sílvia, Tosi, Sébastien, Mandal, Tamoghna, Buske, Christian, Linden, Mika, Albertazzi, Lorenzo, (2017). Super-resolution microscopy unveils dynamic heterogeneities in nanoparticle protein corona Small 13, (41), 1701631

The adsorption of serum proteins, leading to the formation of a biomolecular corona, is a key determinant of the biological identity of nanoparticles in vivo. Therefore, gaining knowledge on the formation, composition, and temporal evolution of the corona is of utmost importance for the development of nanoparticle-based therapies. Here, it is shown that the use of super-resolution optical microscopy enables the imaging of the protein corona on mesoporous silica nanoparticles with single protein sensitivity. Particle-by-particle quantification reveals a significant heterogeneity in protein absorption under native conditions. Moreover, the diversity of the corona evolves over time depending on the surface chemistry and degradability of the particles. This paper investigates the consequences of protein adsorption for specific cell targeting by antibody-functionalized nanoparticles providing a detailed understanding of corona-activity relations. The methodology is widely applicable to a variety of nanostructures and complements the existing ensemble approaches for protein corona study.

JTD Keywords: Heterogeneity, Mesoporous silica nanoparticles, Protein corona, Super-resolution imaging, Targeting

Vilela, D., Stanton, M. M., Parmar, J., Sánchez, S., (2017). Microbots decorated with silver nanoparticles kill bacteria in aqueous media ACS Applied Materials & Interfaces 9, (27), 22093-22100

Water contamination is one of the most persistent problems of public health. Resistance of some pathogens to conventional disinfectants can require the combination of multiple disinfectants or increased disinfectant doses, which may produce harmful byproducts. Here, we describe an efficient method for disinfecting Escherichia coli and removing the bacteria from contaminated water using water self-propelled Janus microbots decorated with silver nanoparticles (AgNPs). The structure of a spherical Janus microbot consists of a magnesium (Mg) microparticle as a template that also functions as propulsion source by producing hydrogen bubbles when in contact with water, an inner iron (Fe) magnetic layer for their remote guidance and collection, and an outer AgNP-coated gold (Au) layer for bacterial adhesion and improving bactericidal properties. The active motion of microbots increases the chances of the contact of AgNPs on the microbot surface with bacteria, which provokes the selective Ag+ release in their cytoplasm, and the microbot self-propulsion increases the diffusion of the released Ag+ ions. In addition, the AgNP-coated Au cap of the microbots has a dual capability of capturing bacteria and then killing them. Thus, we have demonstrated that AgNP-coated Janus microbots are capable of efficiently killing more than 80% of E. coli compared with colloidal AgNPs that killed only less than 35% of E. coli in contaminated water solutions in 15 min. After capture and extermination of bacteria, magnetic properties of the cap allow collection of microbots from water along with the captured dead bacteria, leaving water with no biological contaminants. The presented biocompatible Janus microbots offer an encouraging method for rapid disinfection of water.

JTD Keywords: Bactericidal, Magnetic control, Micromotors, Microswimmers, Self-propulsion, Silver nanoparticles

Ma, X., Sánchez, S., (2017). Bio-catalytic mesoporous Janus nano-motors powered by catalase enzyme Tetrahedron , 73, (33), 4883-4886

Enzyme triggered bio-catalytic reactions convert chemical energy into mechanical force to power micro/nano-machines. Though there have been reports about enzymes powered micro/nano-motors, enzymatic Janus nano-motor smaller than 100 nm has not been reported yet. Here, we prepared an enzyme powered Janus nano-motor by half-capping a thin layer of silicon dioxide (4 nm SiO2) onto a mesoporous silica nanoparticle (MSNP) of 90 nm, enabling asymmetry to the nano-architecture. The nano-motors are chemically powered by the decomposition of H2O2 triggered by the enzyme catalase located at one face of the nanoparticles. The self-propulsion is characterized by dynamic light scattering (DLS) and optical microscopy. The apparent diffusion coefficient was enhanced by 150% compared to their Brownian motion at low H2O2 concentration (i.e. below 3 wt%). Mesoporous nano-motors might serve as active drug delivery nano-systems in future biomedical applications such as intracellular drug delivery.

JTD Keywords: Enzyme catalysis, Janus particles, Mesoporous silica, Nano-motors, Nanomachine, Self-propulsion

Marsal, Maria, Jorba, Ignasi, Rebollo, Elena, Luque, Tomas, Navajas, Daniel, Martín-Blanco, Enrique, (2017). AFM and microrheology in the zebrafish embryo yolk cell Journal of Visualized Experiments Developmental Biology, (129), e56224

Elucidating the factors that direct the spatio-temporal organization of evolving tissues is one of the primary purposes in the study of development. Various propositions claim to have been important contributions to the understanding of the mechanical properties of cells and tissues in their spatiotemporal organization in different developmental and morphogenetic processes. However, due to the lack of reliable and accessible tools to measure material properties and tensional parameters in vivo, validating these hypotheses has been difficult. Here we present methods employing atomic force microscopy (AFM) and particle tracking with the aim of quantifying the mechanical properties of the intact zebrafish embryo yolk cell during epiboly. Epiboly is an early conserved developmental process whose study is facilitated by the transparency of the embryo. These methods are simple to implement, reliable, and widely applicable since they overcome intrusive interventions that could affect tissue mechanics. A simple strategy was applied for the mounting of specimens, AFM recording, and nanoparticle injections and tracking. This approach makes these methods easily adaptable to other developmental times or organisms.

JTD Keywords: Developmental Biology, Zebrafish, Yolk, Atomic Force Microscopy, Cortical Tension, Microrheology, Nanoparticle tracking

Gállego, Isaac, Manning, Brendan, Prades, Joan Daniel, Mir, Mónica, Samitier, Josep, Eritja, Ramon, (2017). DNA-Origami-Aided Lithography for Sub-10 Nanometer Pattern Printing Proceedings Eurosensors 2017 , MDPI (Paris, France) 1, (4), 325

We report the first DNA-based origami technique that can print addressable patterns on surfaces with sub-10 nm resolution. Specifically, we have used a two-dimensional DNA origami as a template (DNA origami stamp) to transfer DNA with pre-programmed patterns (DNA ink) on gold surfaces. The DNA ink is composed of thiol-modified staple strands incorporated at specific positions of the DNA origami stamp to create patterns upon thiol-gold bond formation on the surface (DNA ink). The DNA pattern formed is composed of unique oligonucleotide sequences, each of which is individually addressable. As a proof-of-concept, we created a linear pattern of oligonucleotide-modified gold nanoparticles complementary to the DNA ink pattern. We have developed an in silico model to identify key elements in the formation of our DNA origami-driven lithography and nanoparticle patterning as well as simulate more complex nanoparticle patterns on surfaces.

JTD Keywords: DNA nanotechnology, Lithography, Nanopatterning, Gold nanoparticles, Metasurfaces

De Koker, Stefaan, Cui, Jiwei, Vanparijs, Nane, Albertazzi, Lorenzo, Grooten, Johan, Caruso, Frank, De Geest, Bruno G., (2016). Engineering polymer hydrogel nanoparticles for lymph node-targeted delivery Angewandte Chemie - International Edition 55, (4), 1334-1339

The induction of antigen-specific adaptive immunity exclusively occurs in lymphoid organs. As a consequence, the efficacy by which vaccines reach these tissues strongly affects the efficacy of the vaccine. Here, we report the design of polymer hydrogel nanoparticles that efficiently target multiple immune cell subsets in the draining lymph nodes. Nanoparticles are fabricated by infiltrating mesoporous silica particles (ca. 200 nm) with poly(methacrylic acid) followed by disulfide-based crosslinking and template removal. PEGylation of these nanoparticles does not affect their cellular association in vitro, but dramatically improves their lymphatic drainage in vivo. The functional relevance of these observations is further illustrated by the increased priming of antigen-specific T cells. Our findings highlight the potential of engineered hydrogel nanoparticles for the lymphatic delivery of antigens and immune-modulating compounds.

JTD Keywords: Dendritic cells, Disulfides, Hydrogels, Nanoparticles, Vaccines

Maggi, Claudio, Simmchen, Juliane, Saglimbeni, Filippo, Katuri, Jaideep, Dipalo, Michele, De Angelis, Francesco, Sánchez, Samuel, Di Leonardo, Roberto, (2016). Self-assembly of micromachining systems powered by Janus micromotors Small 12, (4), 446-451

Janus particles can self-assemble around microfabricated gears in reproducible configurations with a high degree of spatial and orientational order. The final configuration maximizes the torque applied on the rotor leading to a unidirectional and steady rotating motion. The interplay between geometry and dynamical behavior leads to the self-assembly of Janus micromotors starting from randomly distributed particles.

JTD Keywords: Active catalytic particles, Microgears, Micromachines, Janus particles, Self-assembly, Self-propulsion

Fernanda, Andrade, Pedro, Fonte, Ana, Costa, Cassilda Cunha, Reis, Rute, Nunes, Andreia, Almeida, Domingos, Ferreira, Mireia, Oliva, Bruno, Sarmento, (2016). Pharmacological and toxicological assessment of innovative self-assembled polymeric micelles as powders for insulin pulmonary delivery Nanomedicine 11, (17), 2305-2317

Aim: Explore the use of polymeric micelles in the development of powders intended for pulmonary delivery of biopharmaceuticals, using insulin as a model protein. Materials & methods: Formulations were assessed in vitro for aerosolization properties and in vivo for efficacy and safety using a streptozotocin-induced diabetic rat model. Results: Powders presented good aerosolization properties like fine particle fraction superior to 40% and a mass median aerodynamic diameter inferior of 6 μm. Endotracheally instilled powders have shown a faster onset of action than subcutaneous administration of insulin at a dose of 10 IU/kg, with pharmacological availabilities up to 32.5% of those achieved by subcutaneous route. Additionally, micelles improved the hypoglycemic effect of insulin. Bronchoalveolar lavage screening for toxicity markers (e.g., lactate dehydrogenase, cytokines) revealed no signs of lung inflammation and cytotoxicity 14 days postadministration. Conclusion: Developed powders showed promising safety and efficacy characteristics for the systemic delivery of insulin by pulmonary administration.

JTD Keywords: Fine particle fraction, Inhalation, Insulin, In vivo, Pharmacological availability, Polymeric micelles, Pulmonary toxicity

Stanton, Morgan M., Simmchen, Juliane, Ma, Xing, Miguel-López, Albert, Sánchez, Samuel, (2016). Biohybrid Janus motors driven by Escherichia coli Advanced Materials Interfaces , 3, (2), 1500505

There has been a significant interest in the development of microswimmers for medical drug and cargo delivery, but the majority of current micromotors rely on toxic fuel sources and materials in their design making them irrelevant for biomedical applications. Bacteria represent an excellent motor alternative, as they are powered using their surrounding biological fluids. For a motile, biohybrid swimmer, Escherichia coli (E. coli) are integrated onto metal capped, polystyrene (PS) Janus particles. Fabrication of the biohybrid is rapid and simple for a microswimmer capable of magnetic guidance and ferrying an anticancer agent. Cell adhesion is regulated as E. coli adheres only to the particle's metal caps allowing the PS surface to be utilized for drug attachment, creating a multifunctional system. E. coli adhesion is investigated on multiple metal caps (Pt, Fe, Ti, or Au) and displays a strong preference to attach to Pt surfaces over other metals. Surface hydrophobicity and surface charge are examined to interpret the cell specific adhesion on the Janus particles. The dual capability of the biohybrid to have guided cell adhesion and localized drug attachment allows the swimmer to have multiple applications for biomedical microswimmers, future bacteria-interface systems, and micro-biorobots.

JTD Keywords: Bacteria adhesion, Biohybrids, Escherichia coli, Janus particles, Microswimmers

Tahirbegi, I.B., Pardo, W.A., Alvira, M., Mir, M., Samitier, J., (2016). Amyloid Aβ 42, a promoter of magnetite nanoparticle formation in Alzheimer's disease Nanotechnology 27, (46), 465102

The accumulation of iron oxides - mainly magnetite - with amyloid peptide is a key process in the development of Alzheimer's disease (AD). However, the mechanism for biogeneration of magnetite inside the brain of someone with AD is still unclear. The iron-storing protein ferritin has been identified as the main magnetite-storing molecule. However, accumulations of magnetite in AD are not correlated with an increase in ferritin, leaving this question unresolved. Here we demonstrate the key role of amyloid peptide Aβ 42, one of the main hallmarks of AD, in the generation of magnetite nanoparticles in the absence of ferritin. The capacity of amyloid peptide to bind and concentrate iron hydroxides, the basis for the formation of magnetite, benefits the spontaneous synthesis of these nanoparticles, even under unfavorable conditions for their formation. Using scanning and transmission electron microscopy, electron energy loss spectroscopy and magnetic force microscopy we characterized the capacity of amyloid peptide Aβ 42 to promote magnetite formation.

JTD Keywords: Alzheimer disease (AD), amyloid peptide Ab42, magnetite nanoparticle, metallobiomolecule, iron oxide, neurodegenerative brain diseases

Silva, N., Muñoz, C., Diaz-Marcos, J., Samitier, J., Yutronic, N., Kogan, M. J., Jara, P., (2016). In situ visualization of the local photothermal effect produced on α-cyclodextrin inclusion compound associated with gold nanoparticles Nanoscale Research Letters 11, 180

Evidence of guest migration in α-cyclodextrin-octylamine (α-CD-OA) inclusion compound (IC) generated via plasmonic heating of gold nanoparticles (AuNPs) has been studied. In this report, we demonstrate local effects generated by laser-mediated irradiation of a sample of AuNPs covered with inclusion compounds on surface-derivatized glass under liquid conditions by atomic force microscopy (AFM). Functionalized AuNPs on the glass and covered by the ICs were monitored by recording images by AFM during 5 h of irradiation, and images showed that after irradiation, a drastic decrease in the height of the AuNPs occurred. The absorption spectrum of the irradiated sample showed a hypsochromic shift from 542 to 536 nm, evidence suggesting that much of the population of nanoparticles lost all of the parts of the overlay of ICs due to the plasmonic heat generated by the irradiation. Mass spectrometry matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) performed on a sample containing a collection of drops obtained from the surface of the functionalized glass provided evidence that the irradiation lead to disintegration of the ICs and therefore exit of the octylamine molecule (the guest) from the cyclodextrin cavity (the matrix).

JTD Keywords: Cyclodextrin inclusion compound, Gold nanoparticles, Guest migration, Plasmonic heating

Ma, X., Jannasch, A., Albrecht, U. R., Hahn, K., Miguel-López, A., Schäffer, E., Sánchez, S., (2015). Enzyme-powered hollow mesoporous Janus nanomotors Nano Letters 15, (10), 7043-7050

The development of synthetic nanomotors for technological applications in particular for life science and nanomedicine is a key focus of current basic research. However, it has been challenging to make active nanosystems based on biocompatible materials consuming nontoxic fuels for providing self-propulsion. Here, we fabricate self-propelled Janus nanomotors based on hollow mesoporous silica nanoparticles (HMSNPs), which are powered by biocatalytic reactions of three different enzymes: catalase, urease, and glucose oxidase (GOx). The active motion is characterized by a mean-square displacement (MSD) analysis of optical video recordings and confirmed by dynamic light scattering (DLS) measurements. We found that the apparent diffusion coefficient was enhanced by up to 83%. In addition, using optical tweezers, we directly measured a holding force of 64 ± 16 fN, which was necessary to counteract the effective self-propulsion force generated by a single nanomotor. The successful demonstration of biocompatible enzyme-powered active nanomotors using biologically benign fuels has a great potential for future biomedical applications.

JTD Keywords: Enzyme, Hollow mesoporous silica nanoparticles, Hybrid motors, Janus particles, Nanomotors, Optical tweezers

Ma, X., Katuri, J., Zeng, Y., Zhao, Y., Sánchez, S., (2015). Surface conductive graphene-wrapped micromotors exhibiting enhanced motion Small 11, (38), 5023–5027

Surface-conductive Janus spherical motors are fabricated by wrapping silica particles with reduced graphene oxide capped with a thin Pt layer. These motors exhibit a 100% enhanced velocity as compared to standard SiO2–Pt motors. Furthermore, the versatility of graphene may open up possibilities for a diverse range of applications from active drug delivery systems to water remediation.

JTD Keywords: Enhanced speed, Graphene wrapping, Janus micromotors, Janus particles, Micromotors, Surface conduction

Baelo, Aida, Levato, Riccardo, Julián, Esther, Crespo, Anna, Astola, José, Gavaldà, Joan, Engel, Elisabeth, Mateos-Timoneda, Miguel Angel, Torrents, Eduard, (2015). Disassembling bacterial extracellular matrix with DNase-coated nanoparticles to enhance antibiotic delivery in biofilm infections Journal of Controlled Release 209, 150-158

Abstract Infections caused by biofilm-forming bacteria are a major threat to hospitalized patients and the main cause of chronic obstructive pulmonary disease and cystic fibrosis. There is an urgent necessity for novel therapeutic approaches, since current antibiotic delivery fails to eliminate biofilm-protected bacteria. In this study, ciprofloxacin-loaded poly(lactic-co-glycolic acid) nanoparticles, which were functionalized with DNase I, were fabricated using a green-solvent based method and their antibiofilm activity was assessed against Pseudomonas aeruginosa biofilms. Such nanoparticles constitute a paradigm shift in biofilm treatment, since, besides releasing ciprofloxacin in a controlled fashion, they are able to target and disassemble the biofilm by degrading the extracellular DNA that stabilize the biofilm matrix. These carriers were compared with free-soluble ciprofloxacin, and ciprofloxacin encapsulated in untreated and poly(lysine)-coated nanoparticles. DNase I-activated nanoparticles were not only able to prevent biofilm formation from planktonic bacteria, but they also successfully reduced established biofilm mass, size and living cell density, as observed in a dynamic environment in a flow cell biofilm assay. Moreover, repeated administration over three days of DNase I-coated nanoparticles encapsulating ciprofloxacin was able to reduce by 95% and then eradicate more than 99.8% of established biofilm, outperforming all the other nanoparticle formulations and the free-drug tested in this study. These promising results, together with minimal cytotoxicity as tested on J774 macrophages, allow obtaining novel antimicrobial nanoparticles, as well as provide clues to design the next generation of drug delivery devices to treat persistent bacterial infections.

JTD Keywords: Pseudomonas aeruginosa, Biofilm, Ciprofloxacin, DNase I, Nanoparticles

Seo, K. D., Kwak, B. K., Sánchez, S., Kim, D. S., (2015). Microfluidic-assisted fabrication of flexible and location traceable organo-motor IEEE Transactions on Nanobioscience , 14, (3), 298-304

In this paper, we fabricate a flexible and location traceable micromotor, called organo-motor, assisted by microfluidic devices and with high throughput. The organo-motors are composed of organic hydrogel material, poly (ethylene glycol) diacrylate (PEGDA), which can provide the flexibility of their structure. For spatial and temporal traceability of the organo-motors under magnetic resonance imaging (MRI), superparamagnetic iron oxide nanoparticles (SPION; Fe3O4) were incorporated into the PEGDA microhydrogels. Furthermore, a thin layer of platinum (Pt) was deposited onto one side of the SPION-PEGDA microhydrogels providing geometrical asymmetry and catalytic propulsion in aqueous fluids containing hydrogen peroxide solution, H2O2. Furthermore, the motion of the organo-motor was controlled by a small external magnet enabled by the presence of SPION in the motor architecture.

JTD Keywords: Flexible, Hydrogel, Magnetic resonance imaging, Microfluidics, Micromotor, Microparticle, Organo-motor, Poly (ethylene glycol) diacrylate, Self-propulsion, Superparamagnetic iron oxide nanoparticles

Fernàndez-Busquets, X., (2014). Toy kit against malaria: Magic bullets, LEGO, Trojan horses and Russian dolls Therapeutic Delivery , 5, (10), 1049-1052

Cuervo, A., Dans, P. D., Carrascosa, J. L., Orozco, M., Gomila, G., Fumagalli, L., (2014). Direct measurement of the dielectric polarization properties of DNA Proceedings of the National Academy of Sciences of the United States of America 111, (35), E3624-E3630

The electric polarizability of DNA, represented by the dielectric constant, is a key intrinsic property that modulates DNA interaction with effector proteins. Surprisingly, it has so far remained unknown owing to the lack of experimental tools able to access it. Here, we experimentally resolved it by detecting the ultraweak polarization forces of DNA inside single T7 bacteriophages particles using electrostatic force microscopy. In contrast to the common assumption of low-polarizable behavior like proteins (εr ~ 2–4), we found that the DNA dielectric constant is ~ 8, considerably higher than the value of ~ 3 found for capsid proteins. State-of-the-art molecular dynamic simulations confirm the experimental findings, which result in sensibly decreased DNA interaction free energy than normally predicted by Poisson–Boltzmann methods. Our findings reveal a property at the basis of DNA structure and functions that is needed for realistic theoretical descriptions, and illustrate the synergetic power of scanning probe microscopy and theoretical computation techniques.

JTD Keywords: Atomic force microscopy, Atomistic simulations, DNA packaging, DNA-ligand binding, Poisson-Boltzmann equation, capsid protein, DNA, double stranded DNA, amino acid composition, article, atomic force microscopy, bacteriophage, bacteriophage T7, dielectric constant, dipole, DNA binding, DNA packaging, DNA structure, electron microscopy, ligand binding, nonhuman, polarization, priority journal, protein analysis, protein DNA interaction, scanning probe microscopy, static electricity, virion, virus capsid, virus particle, atomic force microscopy, atomistic simulations, DNA packaging, DNA-ligand binding, Poisson-Boltzmann equation, Bacteriophage T7, Capsid, Cations, Dielectric Spectroscopy, DNA, DNA, Viral, DNA-Binding Proteins, Electrochemical Techniques, Ligands, Microscopy, Atomic Force, Models, Chemical, Nuclear Proteins

Movellan, J., Urbán, P., Moles, E., de la Fuente, J. M., Sierra, T., Serrano, J. L., Fernàndez-Busquets, X., (2014). Amphiphilic dendritic derivatives as nanocarriers for the targeted delivery of antimalarial drugs Biomaterials 35, (27), 7940-7950

It can be foreseen that in a future scenario of malaria eradication, a varied armamentarium will be required, including strategies for the targeted administration of antimalarial compounds. The development of nanovectors capable of encapsulating drugs and of delivering them to Plasmodium-infected cells with high specificity and efficacy and at an affordable cost is of particular interest. With this objective, dendritic derivatives based on 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) and Pluronic® polymers have been herein explored. Four different dendritic derivatives have been tested for their capacity to encapsulate the antimalarial drugs chloroquine (CQ) and primaquine (PQ), their specific targeting to Plasmodium-infected red blood cells (pRBCs), and their antimalarial activity in vitro against the human pathogen Plasmodium falciparum and in vivo against the rodent malaria species Plasmodium yoelii. The results obtained have allowed the identification of two dendritic derivatives exhibiting specific targeting to pRBCs vs. non-infected RBCs, which reduce the in vitro IC50 of CQ and PQ by ca. 3- and 4-fold down to 4.0 nm and 1.1 μm, respectively. This work on the application of dendritic derivatives to antimalarial targeted drug delivery opens the way for the use of this new type of chemicals in future malaria eradication programs.

JTD Keywords: Antimalarial targeted drug delivery, Dendrimers, Malaria, Nanomedicine, Plasmodium, Polymeric nanoparticles

Marques, J., Moles, E., Urbán, P., Prohens, R., Busquets, M. A., Sevrin, C., Grandfils, C., Fernàndez-Busquets, X., (2014). Application of heparin as a dual agent with antimalarial and liposome targeting activities toward Plasmodium-infected red blood cells Nanomedicine: Nanotechnology, Biology, and Medicine 10, (8), 1719-1728

Heparin had been demonstrated to have antimalarial activity and specific binding affinity for Plasmodium-infected red blood cells (pRBCs) vs. non-infected erythrocytes. Here we have explored if both properties could be joined into a drug delivery strategy where heparin would have a dual role as antimalarial and as a targeting element of drug-loaded nanoparticles. Confocal fluorescence and transmission electron microscopy data show that after 30. min of being added to living pRBCs fluorescein-labeled heparin colocalizes with the intracellular parasites. Heparin electrostatically adsorbed onto positively charged liposomes containing the cationic lipid 1,2-dioleoyl-3-trimethylammonium-propane and loaded with the antimalarial drug primaquine was capable of increasing three-fold the activity of encapsulated drug in Plasmodium falciparum cultures. At concentrations below those inducing anticoagulation of mouse blood in vivo, parasiticidal activity was found to be the additive result of the separate activities of free heparin as antimalarial and of liposome-bound heparin as targeting element for encapsulated primaquine. From the Clinical Editor: Malaria remains an enormous global public health concern. In this study, a novel functionalized heparin formulation used as drug delivery agent for primaquine was demonstrated to result in threefold increased drug activity in cell cultures, and in a murine model it was able to provide these benefits in concentrations below what would be required for anticoagulation. Further studies are needed determine if this approach is applicable in the human disease as well.

JTD Keywords: Heparin, Liposomes, Malaria, Plasmodium, Targeted drug delivery, Heparin, Malaria, Plasmodium, Red blood cell, Targeted drug delivery, Liposomes, 1,2 dioleoyl 3 trimethylammoniopropane, fluorescein, heparin, liposome, nanoparticle, primaquine, adsorption, animal experiment, anticoagulation, antimalarial activity, Article, binding affinity, confocal microscopy, controlled study, drug targeting, encapsulation, erythrocyte, female, fluorescence microscopy, human, human cell, in vivo study, liposomal delivery, mouse, nonhuman, Plasmodium falciparum, transmission electron microscopy

Dalmases, M., Torres, M., Márquez-Kisinousky, L., Almendros, I., Planas, A. M., Embid, C., Martínez-Garcia, M. A., Navajas, D., Farré, R., Montserrat, J. M., (2014). Brain tissue hypoxia and oxidative stress induced by obstructive apneas is different in young and aged rats Sleep , 37, (7), 1249-1256

Study Objectives: To test the hypotheses that brain oxygen partial pressure (PtO2) in response to obstructive apneas changes with age and that it might lead to different levels of cerebral tissue oxidative stress. Design: Prospective controlled animal study. Setting: University laboratory. Participants: Sixty-four male Wistar rats: 32 young (3 mo old) and 32 aged (18 mo). Interventions: Protocol 1: Twenty-four animals were subjected to obstructive apneas (50 apneas/h, lasting 15 sec each) or to sham procedure for 50 min. Protocol 2: Forty rats were subjected to obstructive apneas or sham procedure for 4 h. Measurements and Results: Protocol 1: Real-time PtO2 measurements were performed using a fast-response oxygen microelectrode. During successive apneas cerebral cortex PtO2 presented a different pattern in the two age groups; there was a fast increase in young rats, whereas it remained without significant changes between the beginning and the end of the protocol in the aged group. Protocol 2: Brain oxidative stress assessed by lipid peroxidation increased after apneas in young rats (1.34 ± 0.17 nmol/mg of protein) compared to old ones (0.63 ± 0.03 nmol/mg), where a higher expression of antioxidant enzymes was observed. Conclusions: The results suggest that brain oxidative stress in aged rats is lower than in young rats in response to recurrent apneas, mimicking obstructive sleep apnea. This could be due to the different PtO2 response observed between age groups and the increased antioxidant expression in aged rats.

JTD Keywords: Aging, Animal model, Obstructive apnea, Oxidative stress, Tissue oxygenation, antioxidant, glutathione disulfide, aged, animal experiment, animal model, animal tissue, apnea, arterial oxygen saturation, article, brain cortex, brain oxygen tension, brain tissue, controlled study, groups by age, hypoxia, lipid peroxidation, male, nonhuman, oxidative stress, pressure, priority journal, rat

Urbán, P., Fernàndez-Busquets, X., (2014). Nanomedicine against malaria Current Medicinal Chemistry , 21, (5), 605-629

Malaria is arguably one of the main medical concerns worldwide because of the numbers of people affected, the severity of the disease and the complexity of the life cycle of its causative agent, the protist Plasmodium sp. The clinical, social and economic burden of malaria has led for the last 100 years to several waves of serious efforts to reach its control and eventual eradication, without success to this day. With the advent of nanoscience, renewed hopes have appeared of finally obtaining the long sought-after magic bullet against malaria in the form of a nanovector for the targeted delivery of antimalarial drugs exclusively to Plasmodium-infected cells. Different types of encapsulating structure, targeting molecule, and antimalarial compound will be discussed for the assembly of Trojan horse nanocapsules capable of targeting with complete specificity diseased cells and of delivering inside them their antimalarial cargo with the objective of eliminating the parasite with a single dose. Nanotechnology can also be applied to the discovery of new antimalarials through single-molecule manipulation approaches for the identification of novel drugs targeting essential molecular components of the parasite. Finally, methods for the diagnosis of malaria can benefit from nanotools applied to the design of microfluidic-based devices for the accurate identification of the parasite's strain, its precise infective load, and the relative content of the different stages of its life cycle, whose knowledge is essential for the administration of adequate therapies. The benefits and drawbacks of these nanosystems will be considered in different possible scenarios, including cost-related issues that might be hampering the development of nanotechnology-based medicines against malaria with the dubious argument that they are too expensive to be used in developing areas.

JTD Keywords: Dendrimers, Liposomes, Malaria diagnosis, Nanobiosensors, Nanoparticles, Plasmodium, Polymers, Targeted drug delivery

Fumagalli, L., Edwards, Martin Andrew, Gomila, G., (2014). Quantitative electrostatic force microscopy with sharp silicon tips Nanotechnology 25, (49), 495701 (9)

Electrostatic force microscopy (EFM) probes are typically coated in either metal (radius ~ 30 nm) or highly-doped diamond (radius ~ 100 nm). Highly-doped silicon probes, which offer a sharpened and stable tip apex (radius ~ 1–10 nm) and are usually used only in standard atomic force microscopy, have been recently shown to allow enhanced lateral resolution in quantitative EFM and its application for dielectric constant measurement. Here we present the theoretical modelling required to quantitatively interpret the electrostatic force between these sharpened tips and samples. In contrast to a sphere-capped cone geometry used to describe metal/diamond-coated tips, modelling a sharpened silicon tip requires a geometry comprised of a cone with two different angles. Theoretical results are supported by experimental measurements of metallic substrates and ~10 nm radius dielectric nanoparticles. This work is equally applicable to EFM and other electrical scanned probe techniques, where it allows quantifying electrical properties of nanomaterials and 3D nano-objects with higher resolution.

JTD Keywords: AFM, Dielectric constant, EFM, Dielectrics, Nanoparticles, Sharp tips

Melo, E., Cárdenes, N., Garreta, E., Luque, T., Rojas, M., Navajas, D., Farré, R., (2014). Inhomogeneity of local stiffness in the extracellular matrix scaffold of fibrotic mouse lungs Journal of the Mechanical Behavior of Biomedical Materials , 37, 186-195

Lung disease models are useful to study how cell engraftment, proliferation and differentiation are modulated in lung bioengineering. The aim of this work was to characterize the local stiffness of decellularized lungs in aged and fibrotic mice. Mice (2- and 24-month old; 14 of each) with lung fibrosis (N=20) and healthy controls (N=8) were euthanized after 11 days of intratracheal bleomycin (fibrosis) or saline (controls) infusion. The lungs were excised, decellularized by a conventional detergent-based (sodium-dodecyl sulfate) procedure and slices of the acellular lungs were prepared to measure the local stiffness by means of atomic force microscopy. The local stiffness of the different sites in acellular fibrotic lungs was very inhomogeneous within the lung and increased according to the degree of the structural fibrotic lesion. Local stiffness of the acellular lungs did not show statistically significant differences caused by age. The group of mice most affected by fibrosis exhibited local stiffness that were ~2-fold higher than in the control mice: from 27.2±1.64 to 64.8±7.1. kPa in the alveolar septa, from 56.6±4.6 to 99.9±11.7. kPa in the visceral pleura, from 41.1±8.0 to 105.2±13.6. kPa in the tunica adventitia, and from 79.3±7.2 to 146.6±28.8. kPa in the tunica intima. Since acellular lungs from mice with bleomycin-induced fibrosis present considerable micromechanical inhomogeneity, this model can be a useful tool to better investigate how different degrees of extracellular matrix lesion modulate cell fate in the process of organ bioengineering from decellularized lungs.

JTD Keywords: Ageing, Atomic force microscopy, Decellularization, Lung fibrosis, Tissue engineering, Atomic force microscopy, Biological organs, Peptides, Sodium dodecyl sulfate, Sodium sulfate, Tissue engineering, Ageing, Decellularization, Extracellular matrices, Healthy controls, Inhomogeneities, Lung fibrosis, Micro-mechanical, Statistically significant difference, Mammals, bleomycin, adventitia, animal experiment, animal model, article, atomic force microscopy, bleomycin-induced pulmonary fibrosis, cell fate, controlled study, extracellular matrix, female, intima, lung alveolus, lung fibrosis, lung mechanics, mechanical probe, microenvironment, mouse, nonhuman, pleura, priority journal, rigidity, tissue engineering

Uriarte, J. J., Nonaka, P. N., Campillo, N., Palma, R. K., Melo, E., de Oliveira, L. V. F., Navajas, D., Farré, R., (2014). Mechanical properties of acellular mouse lungs after sterilization by gamma irradiation Journal of the Mechanical Behavior of Biomedical Materials , 40, 168-177

Lung bioengineering using decellularized organ scaffolds is a potential alternative for lung transplantation. Clinical application will require donor scaffold sterilization. As gamma-irradiation is a conventional method for sterilizing tissue preparations for clinical application, the aim of this study was to evaluate the effects of lung scaffold sterilization by gamma irradiation on the mechanical properties of the acellular lung when subjected to the artificial ventilation maneuvers typical within bioreactors. Twenty-six mouse lungs were decellularized by a sodium dodecyl sulfate detergent protocol. Eight lungs were used as controls and 18 of them were submitted to a 31kGy gamma irradiation sterilization process (9 kept frozen in dry ice and 9 at room temperature). Mechanical properties of acellular lungs were measured before and after irradiation. Lung resistance (RL) and elastance (EL) were computed by linear regression fitting of recorded signals during mechanical ventilation (tracheal pressure, flow and volume). Static (Est) and dynamic (Edyn) elastances were obtained by the end-inspiratory occlusion method. After irradiation lungs presented higher values of resistance and elastance than before irradiation: RL increased by 41.1% (room temperature irradiation) and 32.8% (frozen irradiation) and EL increased by 41.8% (room temperature irradiation) and 31.8% (frozen irradiation). Similar increases were induced by irradiation in Est and Edyn. Scanning electron microscopy showed slight structural changes after irradiation, particularly those kept frozen. Sterilization by gamma irradiation at a conventional dose to ensure sterilization modifies acellular lung mechanics, with potential implications for lung bioengineering.

JTD Keywords: Gamma irradiation, Lung bioengineering, Lung decellularization, Organ scaffold, Pulmonary mechanics, Decellularization, Gamma irradiation, Mouse lung, Pulmonary mechanics, dodecyl sulfate sodium, animal tissue, Article, artificial ventilation, bioengineering, bioreactor, compliance (physical), controlled study, freezing, gamma irradiation, lung, lung mechanics, lung resistance, male, mouse, nonhuman, room temperature, scanning electron microscopy, tissue scaffold, trachea pressure

Rajzer, I., Menaszek, E., Kwiatkowski, R., Planell, J. A., Castaño, O., (2014). Electrospun gelatin/poly(ε-caprolactone) fibrous scaffold modified with calcium phosphate for bone tissue engineering Materials Science and Engineering: C 44, 183-190

In this study gelatin (Gel) modified with calcium phosphate nanoparticles (SG5) and polycaprolactone (PCL) were used to prepare a 3D bi-layer scaffold by collecting electrospun PCL and gelatin/SG5 fibers separately in the same collector. The objective of this study was to combine the desired properties of PCL and Gel/SG5 in the same scaffold in order to enhance mineralization, thus improving the ability of the scaffold to bond to the bone tissue. The scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and the wide angle X-ray diffraction (WAXD) measurements confirmed that SG5 nanoparticles were successfully incorporated into the fibrous gelatin matrix. The composite Gel/SG5/PCL scaffold exhibited more enhanced mechanical properties than individual Gel and Gel/SG5 scaffolds. The presence of SG5 nanoparticles accelerated the nucleation and growth of apatite crystals on the surface of the composite Gel/SG5/PCL scaffold in simulated body fluid (SBF). The osteoblast response in vitro to developed electrospun scaffolds (PCL and Gel/SG5/PCL) was investigated by using normal human primary NHOst cell lines. NHOst cell culture studies showed that higher alkaline phosphatase (ALP) activity and better mineralization were obtained in the case of composite materials than in pure PCL scaffolds. The mechanically strong PCL scaffold served as a skeleton, while the Gel/SG5 fibers facilitated cell spreading and mineralization of the scaffold.

JTD Keywords: Bilayer fibrous scaffold, Ceramic nanoparticles, Electrospinning, Gelatin, Polycaprolactone, Biomechanics, Bone, Calcium phosphate, Cell culture, Electrospinning, Fourier transform infrared spectroscopy, Mechanical properties, Mineralogy, Nanoparticles, Phosphatases, Polycaprolactone, Scanning electron microscopy, X ray diffraction, Polycaprolactone, Alkaline phosphatase activity, Bone tissue engineering, Calcium phosphate nanoparticles, Ceramic nanoparticles, Fibrous scaffolds, Gelatin, Simulated body fluids, Wide-angle x-ray diffraction, Electrospuns, Scaffolds (biology), Electrospinning

Sachot, N., Engel, E., Castaño, O., (2014). Hybrid organic-inorganic scaffolding biomaterials for regenerative therapies Current Organic Chemistry , 18, (18), 2299-2314

The introduction of hybrid materials in regenerative medicine has solved some problems related to the mechanical and bioactive properties of biomaterials. Calcium phosphates and their derivatives have provided the basis for inorganic components, thanks to their good bioactivity, especially in bone regeneration. When mixed with biodegradable polymers, the result is a synergic association that mimics the composition of many tissues of the human body and, additionally, exhibits suitable mechanical properties. Together with the development of nanotechnology and new synthesis methods, hybrids offer a promising option for the development of a third or fourth generation of smart biomaterials and scaffolds to guide the regeneration of natural tissues, with an optimum efficiency/cost ratio. Their potential bioactivity, as well as other valuable features of hybrids, open promising new pathways for their use in bone regeneration and other tissue repair therapies. This review provides a comprehensive overview of the different hybrid organic-inorganic scaffolding biomaterials developed so far for regenerative therapies, especially in bone. It also looks at the potential for research into hybrid materials for other, softer tissues, which is still at an initial stage, but with very promising results.

JTD Keywords: Biodegradable polymer, Hybrid materials, Nanoparticles, Ormoglass

Nonaka, P. N., Uriarte, J. J., Campillo, N., Melo, E., Navajas, D., Farré, R., Oliveira, L. V. F., (2014). Mechanical properties of mouse lungs along organ decellularization by sodium dodecyl sulfate Respiratory Physiology & Neurobiology , 200, 1-5

Lung decellularization is based on the use of physical, chemical, or enzymatic methods to break down the integrity of the cells followed by a treatment to extract the cellular material from the lung scaffold. The aim of this study was to characterize the mechanical changes throughout the different steps of lung decellularization process. Four lungs from mice (C57BL/6) were decellularized by using a conventional protocol based on sodium dodecyl sulfate. Lungs resistance (RL) and elastance (EL) were measured along decellularization steps and were computed by linear regression fitting of tracheal pressure, flow, and volume during mechanical ventilation. Transients differences found were more distinct in an intermediate step after the lungs were rinsed with deionized water and treated with 1% SDS, whereupon the percentage of variation reached approximately 80% for resistance values and 30% for elastance values. In conclusion, although a variation in extracellular matrix stiffness was observed during the decellularization process, this variation can be considered negligible overall because the resistance and elastance returned to basal values at the final decellularization step.

JTD Keywords: Lung bioengineering, Lung decellularization, Organ scaffold, dodecyl sulfate sodium, animal tissue, article, artificial ventilation, compliance (physical), controlled study, enzyme chemistry, extracellular matrix, female, flow, lung, lung decellularization, lung pressure, lung resistance, mouse, nonhuman, positive end expiratory pressure, priority journal, rigidity, tissue engineering, trachea pressure

Riggio, C., Nocentini, S., Catalayud, M. P., Goya, G. F., Cuschieri, A., Raffa, V., del Río, J. A., (2013). Generation of magnetized olfactory ensheathing cells for regenerative studies in the central and peripheral nervous tissue International Journal of Molecular Sciences 14, (6), 10852-10868

As olfactory receptor axons grow from the peripheral to the central nervous system (CNS) aided by olfactory ensheathing cells (OECs), the transplantation of OECs has been suggested as a plausible therapy for spinal cord lesions. The problem with this hypothesis is that OECs do not represent a single homogeneous entity, but, instead, a functionally heterogeneous population that exhibits a variety of responses, including adhesion and repulsion during cell-matrix interactions. Some studies report that the migratory properties of OECs are compromised by inhibitory molecules and potentiated by chemical gradients. In this paper, we report a system based on modified OECs carrying magnetic nanoparticles as a proof of concept experiment enabling specific studies aimed at exploring the potential of OECs in the treatment of spinal cord injuries. Our studies have confirmed that magnetized OECs (i) survive well without exhibiting stress-associated cellular responses; (ii) in vitro, their migration can be modulated by magnetic fields; and (iii) their transplantation in organotypic slices of spinal cord and peripheral nerve showed positive integration in the model. Altogether, these findings indicate the therapeutic potential of magnetized OECs for CNS injuries.

JTD Keywords: Magnetic nanoparticle, Nerve regeneration, Olfactory ensheathing cell, Organotypic culture

Penon, O., Novo, S., Duran, S., Ibanez, E., Nogues, C., Samitier, J., Duch, M., Plaza, J. A., Perez-Garcia, L., (2012). Efficient biofunctionalization of polysilicon barcodes for adhesion to the zona pellucida of mouse embryos Bioconjugate Chemistry , 23, (12), 2392-2402

Cell tracking is an emergent area in nano-biotechnology, promising the study of individual cells or the identification of populations of cultured cells. In our approach, microtools designed for extracellular tagging are prepared, because using biofunctionalized polysilicon barcodes to tag cell membranes externally avoids the inconveniences of cell internalization. The crucial covalent biofunctionalization process determining the ultimate functionality was studied in order to find the optimum conditions to link a biomolecule to a polysilicon barcode surface using a self-assembled monolayer (SAM) as the connector. Specifically, a lectin (wheat germ agglutinin, WGA) was used because of its capacity to recognize some specific carbohydrates present on the surface of most mammalian cells. Self-assembled monolayers were prepared on polysilicon surfaces including aldehyde groups as terminal functions to study the suitability of their covalent chemical bonding to WGA. Some parameters, such as the polysilicon surface roughness or the concentration of WGA, proved to be crucial for successful biofunctionalization and bioactivity. The SAMs were characterized by contact angle measurements, time-of-flight secondary ion mass spectrometry (TOF-SIMS), laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF MS), and atomic force microscopy (AFM). The biofunctionalization step was also characterized by fluorescence microscopy and, in the case of barcodes, by adhesion experiments to the zona pellucida of mouse embryos. These experiments showed high barcode retention rates after 96 h of culture as well as high embryo viability to the blastocyst stage, indicating the robustness of the biofunctionalization and, therefore, the potential of these new microtools to be used for cell tagging.

JTD Keywords: Self-assembled monolayers, Wheat-germ-agglutinin, Protein immobilization strategies, Mass-spectrometry, Cell-surface, Petide, Binding, Identifications, Nanoparticles, Recognition

Urban, P., Valle-Delgado, J. J., Moles, E., Marques, J., Diez, C., Fernàndez-Busquets, X., (2012). Nanotools for the delivery of antimicrobial peptides Current Drug Targets , 13, (9), 1158-1172

Antimicrobial peptide drugs are increasingly attractive therapeutic agents as their roles in physiopathological processes are being unraveled and because the development of recombinant DNA technology has made them economically affordable in large amounts and high purity. However, due to lack of specificity regarding the target cells, difficulty in attaining them, or reduced half-lives, most current administration methods require high doses. On the other hand, reduced specificity of toxic drugs demands low concentrations to minimize undesirable side-effects, thus incurring the risk of having sublethal amounts which favour the appearance of resistant microbial strains. In this scenario, targeted delivery can fulfill the objective of achieving the intake of total quantities sufficiently low to be innocuous for the patient but that locally are high enough to be lethal for the infectious agent. One of the major advances in recent years has been the size reduction of drug carriers that have dimensions in the nanometer scale and thus are much smaller than -and capable of being internalized by- many types of cells. Among the different types of potential antimicrobial peptide-encapsulating structures reviewed here are liposomes, dendritic polymers, solid core nanoparticles, carbon nanotubes, and DNA cages. These nanoparticulate systems can be functionalized with a plethora of biomolecules providing specificity of binding to particular cell types or locations; as examples of these targeting elements we will present antibodies, DNA aptamers, cell-penetrating peptides, and carbohydrates. Multifunctional Trojan horse-like nanovessels can be engineered by choosing the adequate peptide content, encapsulating structure, and targeting moiety for each particular application.

JTD Keywords: Antibodies, Aptamers, Dendrimers, Liposomes, Nanomedicine, Nanoparticles, Nanovectors, Targeting

Levato, Riccardo, Mateos-Timoneda, Miguel A., Planell, Josep A., (2012). Preparation of biodegradable polylactide microparticles via a biocompatible procedure Macromolecular Bioscience 12, (4), 557-566

PLA MPs are prepared via a novel and toxic-chemical-free fabrication route using ethyl lactate, a green solvent and FDA-approved aroma. MPs are obtained by a solution jet break-up and solvent displacement method. Adjusting flow parameters allows the tuning of MPs size between 60 and 180 µm, with reduced polydispersity. Morphological analysis shows microporous particles with Janus-like surface. A fluorophore is successfully loaded into the MPs during their formation step. This versatile green solvent-based procedure is proven to be suitable for drug encapsulation and delivery applications. The method may be extended to different droplet generation techniques.

JTD Keywords: Biocompatibility, Biodegradable, Green solvents, Microparticles, Poly(lactic acid)

Serra, T., Navarro, M., Planell, J. A., (2012). Fabrication and characterization of biodegradable composite scaffolds for tissue engineering Innovative Developments in Virtual and Physical Prototyping 5th International Conference on Advanced Research and Rapid Prototyping (ed. Margarida, T., Ferreira, D.), Taylor & Francis (Leiria, Portugal) VR@P, 67-72

In this study, polylactic acid (PLA) and polyethylene glycol (PEG) were combined with soluble CaP glass particles and processed by rapid prototyping to obtain fully biodegradable structures for Tissue Engineering applications. The obtained 3D biodegradable structures were characterized in terms of their architecture and mechanical properties. The scaffold morphology, internal micro-architecture and mechanical properties were evaluated using Scanning Electron Microscopy (SEM), micro-computed tomography (micro-CT) and mechanical testing, respectively. Well defined structures with pore size of 350-400μm (in the axial view), struts width of approximately 70-80μm, and a porosity ranging between 60-65% were obtained. The combination RP and PLA/PEG/CaP glass turned into promising fully degradable, mechanically stable, bioactive and biocompatible composite scaffolds for TE.

JTD Keywords: Axial view, Biodegradable composites, Composite scaffolds, Glass particles, Mechanically stable, Micro architectures, Micro computed tomography (micro-CT), Poly lactic acid, Scaffold morphology, Tissue engineering applications, Well-defined structures, Bioactive glass, Mechanical properties, Mechanical testing, Polyethylene glycols, Polymer blends, Rapid prototyping, Scaffolds (biology), Scanning electron microscopy, Computerized tomography

Valle-Delgado, J. J., Molina-Bolívar, J. A., Galisteo-González, F., Gálvez-Ruiz, M. J., (2011). Evidence of hydration forces between proteins Current Opinion in Colloid and Interface Science , 16, (6), 572-578

Proteins are fundamental molecules in biology that are also involved in a wide range of industrial and biotechnological processes. Consequently, many works in the literature have been devoted to the study of protein-protein and protein-surface interactions in aqueous solutions. The results have been usually interpreted within the frame of the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory for colloidal systems. However, against the DLVO predictions, striking evidence of repulsive forces between proteins at high salt concentrations has been observed in different works based on the analysis of the second virial coefficient or on the direct measurement of protein interaction with an atomic force microscope. Hydration forces due to the adsorption of hydrated cations onto the negatively charged protein surfaces have been invoked to rationalize this anomalous repulsion. The hydration forces between proteins provide protein-covered particles with a non-DLVO colloidal stability at high salt concentrations, as different studies in the literature has proven. This review summarizes the most relevant results published so far on the presence of hydration forces between proteins and protein-coated colloidal particles.

JTD Keywords: Colloidal particles, Colloidal stability, Hydrated ions, Hydration forces, Proteins

Ivon Rodriguez-Villarreal, Angeles, Tarn, Mark D., Madden, Leigh A., Lutz, Julia B., Greenman, John, Samitier, Josep, Pamme, Nicole, (2011). Flow focussing of particles and cells based on their intrinsic properties using a simple diamagnetic repulsion setup Lab on a Chip 11, (7), 1240-1248

The continuous flow focussing and manipulation of particles and cells are important factors in microfluidic applications for performing accurate and reproducible procedures downstream. Many particle focussing methods require complex setups or channel designs that can limit the process and its applications. Here, we present diamagnetic repulsion as a simple means of focussing objects in continuous flow, based only on their intrinsic properties without the requirement of any label. Diamagnetic polystyrene particles were suspended in a paramagnetic medium and pumped through a capillary between a pair of permanent magnets, whereupon the particles were repelled by each magnet into the central axis of the capillary, thus achieving focussing. By investigating this effect, we found that the focussing was greatly enhanced with (i) increased magnetic susceptibility of the medium, (ii) reduced flow rate of the suspension, (iii) increased particle size, and (iv) increased residence time in the magnetic field. Furthermore, we applied diamagnetic repulsion to the flow focussing of living, label-free HaCaT cells.

JTD Keywords: Feeble magnetic substances, On-chip, Blood-cells, Microfluidic device, Separation, Field, Levitation, Magnetophoresis, Fractionation, Nanoparticles

Kodippili, G. C., Spector, J., Kang, G. E., Liu, H., Wickrema, A., Ritchie, K., Low, P. S., (2010). Analysis of the kinetics of band 3 diffusion in human erythroblasts during assembly of the erythrocyte membrane skeleton British Journal of Haematology , 150, (5), 592-600

Summary During definitive erythropoiesis, erythroid precursors undergo differentiation through multiple nucleated states to an enucleated reticulocyte, which loses its residual RNA/organelles to become a mature erythrocyte. Over the course of these transformations, continuous changes in membrane proteins occur, including shifts in protein abundance, rates of expression, isoform prominence, states of phosphorylation, and stability. In an effort to understand when assembly of membrane proteins into an architecture characteristic of the mature erythrocyte occurs, we quantitated the lateral diffusion of the most abundant membrane protein, band 3 (AE1), during each stage of erythropoiesis using single particle tracking. Analysis of the lateral trajectories of individual band 3 molecules revealed a gradual reduction in mobility of the anion transporter as erythroblasts differentiated. Evidence for this progressive immobilization included a gradual decline in diffusion coefficients as determined at a video acquisition rate of 120 frames/s and a decrease in the percentage of compartment sizes >100 nm. Because complete acquisition of the properties of band 3 seen in mature erythrocytes is not observed until circulating erythrocytes are formed, we suggest that membrane maturation involves a gradual and cooperative assembly process that is not triggered by the synthesis of any single protein.

JTD Keywords: Band 3 diffusion, Erythrocyte, Progenitor cells, Single particle tracking, Streptavidin quantum dot

Toset, J., Gomila, G., (2010). Three-dimensional manipulation of gold nanoparticles with electro-enhanced capillary forces Applied Physics Letters , 96, (4), 043117

We demonstrate the possibility to manipulate 25 nm radius gold nanoparticles in the three spatial dimensions with an atomic force microscope with the use of electroenhanced capillary forces. We show that an enhanced water-bridge can be electrostatically induced between a conducting probe and a metallic nanoparticle by the application of a voltage pulse, which is able to exert a pulling capillary force on the nanoparticle strong enough to detach it from the substrate. The nanoparticle can then be moved, attached to the probe, and placed back to the desired location on the substrate simply by contacting it.

JTD Keywords: Atomic force microscopy, Capillarity, Gold, Nanoparticles, Nanotechnology

Fernandez, Javier G., Mills, C. A., Samitier, J., (2009). Complex microstructured 3D surfaces using chitosan biopolymer Small 5, (5), 614-620

A technique for producing micrometer-scale structures over large, nonplanar chitosan surfaces is described. The technique makes use of the rheological characteristics (deformability) of the chitosan to create freestanding, three-dimensional scaffolds with controlled shapes, incorporating defined microtopography. The results of an investigation into the technical limits of molding different combinations of shapes and microtopographies are presented, highlighting the versatility of the technique when used irrespectively with inorganic or delicate organic moulds. The final, replicated scaffolds presented here are patterned with arrays of one-micrometer-tall microstructures over large areas. Structural integrity is characterized by the measurement of structural degradation. Human umbilical vein endothelial cells cultured on a tubular scaffold show that early cell growth is conditioned by the microtopography and indicate possible uses for the structures in biomedical applications. For those applications requiring improved chemical and mechanical resistance, the structures can be replicated in poly(dimethyl siloxane).

JTD Keywords: Biocompatible Materials/ chemistry, Cell Adhesion, Cell Culture Techniques/ methods, Cell Proliferation, Cells, Cultured, Chitosan/ chemistry, Crystallization/methods, Endothelial Cells/ cytology/ physiology, Humans, Materials Testing, Nanostructures/ chemistry/ ultrastructure, Nanotechnology/methods, Particle Size, Surface Properties, Tissue Engineering/methods

Arteaga, O., Escudero, C., Oncins, G., El-Hachemic, Z., Llorens, J., Crusats, J., Canillas, A., Ribo, J. M., (2009). Reversible mechanical induction of optical activity in solutions of soft-matter nanophases Chemistry - An Asian Journal , 4, (11), 1687-1696

Nanophases of J-aggregates of several achiral amphiphilic porphyrins, which have thin long acicular shapes (nanoribbons), show the immediate and reversible formation of a stationary mechano-chiral state in the solution by vortex stirring, as detected by their circular dichroic signals measured by 2-modulator generallized ellipsometry. The results suggest that when a macroscopic chiral force creates supramolecular chirality, it also creates an enantiomeric excess of screw distortions, which may be detected by their excitonic absorption. An explanation on the effect of the shear flow gradients is proposed on the basis of the orientation of the rotating particles in the vortex and the size, shape, and mechanical properties of the nanoparticles.

JTD Keywords: Chirality, Circular dichroism, Nanoparticles, Selfassembly, Supramolecular chemistry

Engel, E., Michiardi, A., Navarro, M., Lacroix, D., Planell, J. A., (2008). Nanotechnology in regenerative medicine: the materials side Trends in Biotechnology , 26, (1), 39-47

Regenerative medicine is an emerging multidisciplinary field that aims to restore, maintain or enhance tissues and hence organ functions. Regeneration of tissues can be achieved by the combination of living cells, which will provide biological functionality, and materials, which act as scaffolds to support cell proliferation. Mammalian cells behave in vivo in response to the biological signals they receive from the surrounding environment, which is structured by nanometre-scaled components. Therefore, materials used in repairing the human body have to reproduce the correct signals that guide the cells towards a desirable behaviour. Nanotechnology is not only an excellent tool to produce material structures that mimic the biological ones but also holds the promise of providing efficient delivery systems. The application of nanotechnology to regenerative medicine is a wide issue and this short review will only focus on aspects of nanotechnology relevant to biomaterials science. Specifically, the fabrication of materials, such as nanoparticles and scaffolds for tissue engineering, and the nanopatterning of surfaces aimed at eliciting specific biological responses from the host tissue will be addressed.

JTD Keywords: Animals, Biocompatible Materials/ metabolism, Humans, Nanoparticles, Nanotechnology/ methods, Regenerative Medicine/ methods, Tissue Scaffolds

Olmedo, Ivonne, Araya, Eyleen, Sanz, Fausto, Medina, Elias, Arbiol, Jordi, Toledo, Pedro, Àlvarez-Lueje, Alejandro, Giralt, Ernest, Kogan, Marcelo J., (2008). How changes in the sequence of the peptide CLPFFD-NH2 can modify the conjugation and stability of gold nanoparticles and their affinity for beta-amyloid fibrils Bioconjugate Chemistry , 19, (6), 1154-1163

In a previous work, we studied the interaction of β-amyloid fibrils (Aβ) with gold nanoparticles (AuNP) conjugated with the peptide CLPFFD-NH2. Here, we studied the effect of changing the residue sequence of the peptide CLPFFD-NH2 on the efficiency of conjugation to AuNP, the stability of the conjugates, and the affinity of the conjugates to the Aβ fibrils. We conjugated the AuNP with CLPFFD-NH2 isomeric peptides (CDLPFF-NH2 and CLPDFF-NH2) and characterized the resulting conjugates with different techniques including UV−Vis, TEM, EELS, XPS, analysis of amino acids, agarose gel electrophoresis, and CD. In addition, we determined the proportion of AuNP bonded to the Aβ fibrils by ICP-MS. AuNP-CLPFFD-NH2 was the most stable of the conjugates and presented more affinity for Aβ fibrils with respect to the other conjugates and bare AuNP. These findings help to better understand the way peptide sequences affect conjugation and stability of AuNP and their interaction with Aβ fibrils. The peptide sequence, the steric effects, and the charge and disposition of hydrophilic and hydrophobic residues are crucial parameters when considering the design of AuNP peptide conjugates for biomedical applications.

JTD Keywords: Self-assembled monolayers, Aggregation, Dispersions, Adsorption, Particles, Design, Size