by Keyword: carriers
Hamelmann NM, Paats JD, Avalos-Padilla Y, Lantero E, Spanos L, Siden-Kiamos I, Fernàndez-Busquets X, Paulusse JMJ, (2023). Single-Chain Polymer Nanoparticles Targeting the Ookinete Stage of Malaria Parasites Acs Infectious Diseases 9, 56-64
Malaria is an infectious disease transmitted by mosquitos, whose control is hampered by drug resistance evolution in the causing agent, protist parasites of the genus Plasmodium, as well as by the resistance of the mosquito to insecticides. New approaches to fight this disease are, therefore, needed. Research into targeted drug delivery is expanding as this strategy increases treatment efficacies. Alternatively, targeting the parasite in humans, here we use single-chain polymer nanoparticles (SCNPs) to target the parasite at the ookinete stage, which is one of the stages in the mosquito. This nanocarrier system provides uniquely sized and monodispersed particles of 5-20 nm, via thiol-Michael addition. The conjugation of succinic anhydride to the SCNP surface provides negative surface charges that have been shown to increase the targeting ability of SCNPs to Plasmodium berghei ookinetes. The biodistribution of SCNPs in mosquitos was studied, showing the presence of SCNPs in mosquito midguts. The presented results demonstrate the potential of anionic SCNPs for the targeting of malaria parasites in mosquitos and may lead to progress in the fight against malaria.
JTD Keywords: antimalarial, atovaquone, carriers, delivery, drug-conjugate, heparin, intramolecular crosslinking, plasmodium berghei, therapy, thiol-michael addition, transmission, Atovaquone, Drug-conjugate, Intramolecular crosslinking, Plasmodium berghei, Plasmodium-falciparum, Single chain polymer nanoparticles, Thiol-michael addition
Solomon M, Loeck M, Silva-Abreu M, Moscoso R, Bautista R, Vigo M, Muro S, (2022). Altered blood-brain barrier transport of nanotherapeutics in lysosomal storage diseases Journal Of Controlled Release 349, 1031-1044
Treatment of neurological lysosomal storage disorders (LSDs) are limited because of impermeability of the blood-brain barrier (BBB) to macromolecules. Nanoformulations targeting BBB transcytosis are being explored, but the status of these routes in LSDs is unknown. We studied nanocarriers (NCs) targeted to the transferrin receptor (TfR), ganglioside GM1 or ICAM1, associated to the clathrin, caveolar or cell adhesion molecule (CAM) routes, respectively. We used brain endothelial cells and mouse models of acid sphingomyelinase-deficient Niemann Pick disease (NPD), and postmortem LSD patients' brains, all compared to respective controls. NC transcytosis across brain endothelial cells and brain distribution in mice were affected, yet through different mechanisms. Reduced TfR and clathrin expression were found, along with decreased transcytosis in cells and mouse brain distribution. Caveolin-1 expression and GM1 transcytosis were also reduced, yet increased GM1 levels seemed to compensate, providing similar NC brain distribution in NPD vs. control mice. A tendency to lower NHE-1 levels was seen, but highly increased ICAM1 expression in cells and human brains correlated with increased transcytosis and brain distribution in mice. Thus, transcytosis-related alterations in NPD and likely other LSDs may impact therapeutic access to the brain, illustrating the need for these mechanistic studies.Copyright © 2022 Elsevier B.V. All rights reserved.
JTD Keywords: acid sphingomyelinase, antibody-affinity, blood -brain barrier, drug-delivery, icam-1-targeted nanocarriers, in-vivo, mediated endocytosis, model, neurological diseases, niemann-pick, targeted nanocarriers, trafficking, transcytosis pathways, Blood-brain barrier, Central-nervous-system, Lysosomal storage disorders, Neurological diseases, Targeted nanocarriers, Transcytosis pathways
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
Enshaei, H, Molina, BG, Puiggali-Jou, A, Saperas, N, Aleman, C, (2022). Polypeptide hydrogel loaded with conducting polymer nanoparticles as electroresponsive delivery system of small hydrophobic drugs European Polymer Journal 173, 111199
A hydrogel/nanoparticle-loaded system for the controlled delivery of small hydrophobic drugs has been prepared using poly(gamma-glutamic acid) (PGGA), a naturally occurring biopolymer made of glutamic acid units connected by amide linkages between alpha-amino and gamma-carboxylic acid groups, and poly(3,4-ethylenedioxythiophene) (PEDOT), a very stable conducting polymer with excellent electrochemical response. Specifically, curcumin (CUR)-loaded PEDOT nanoparticles (PEDOT/CUR) were incorporated to the PGGA hydrogel during the crosslinking reaction. After chemical, morphological and electrochemical characterization, the release profiles of PEDOT/CUR and PGGA/PEDOT/CUR system have been compared in absence and presence of electrical stimuli, which consisted on the application of a voltage of -0.5 V for 15 min every 24 h. Results show that the release is higher for electrically stimulated systems by more than twice, even though due to its hydrophobicity and poor solubility in water the release was relatively slow in both cases. This feature could be advantageous when the therapeutic treatment requires slow, controlled and sustained CUR release.
JTD Keywords: 4-ethylenedioxythiophene), Acid, Controlled-release, Curcumi n, Curcumin, Electrostimulated release, Nanocarriers, Pedotpss, Poly( ?-glutamic acid), Poly(3
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
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
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,
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
Rubí-Sans G, Nyga A, Rebollo E, Pérez-Amodio S, Otero J, Navajas D, Mateos-Timoneda MA, Engel E, (2021). Development of Cell-Derived Matrices for Three-Dimensional in Vitro Cancer Cell Models Acs Applied Materials & Interfaces 13, 44108-44123
Most morphogenetic and pathological processes are driven by cells responding to the surrounding matrix, such as its composition, architecture, and mechanical properties. Despite increasing evidence for the role of extracellular matrix (ECM) in tissue and disease development, many in vitro substitutes still fail to effectively mimic the native microenvironment. We established a novel method to produce macroscale (>1 cm) mesenchymal cell-derived matrices (CDMs) aimed to mimic the fibrotic tumor microenvironment surrounding epithelial cancer cells. CDMs are produced by human adipose mesenchymal stem cells cultured in sacrificial 3D scaffold templates of fibronectin-coated poly-lactic acid microcarriers (MCs) in the presence of macromolecular crowders. We showed that decellularized CDMs closely mimic the fibrillar protein composition, architecture, and mechanical properties of human fibrotic ECM from cancer masses. CDMs had highly reproducible composition made of collagen types I and III and fibronectin ECM with tunable mechanical properties. Moreover, decellularized and MC-free CDMs were successfully repopulated with cancer cells throughout their 3D structure, and following chemotherapeutic treatment, cancer cells showed greater doxorubicin resistance compared to 3D culture in collagen hydrogels. Collectively, these results support the use of CDMs as a reproducible and tunable tool for developing 3D in vitro cancer models.
JTD Keywords: 3d cell-derived matrices, adipose mesenchymal stem cells, collagen matrix, colorectal adenocarcinoma, cytotoxicity assay, deposition, expansion, extracellular microenvironment, extracellular-matrix, fibronectin, growth, macromolecular crowders, microcarriers, scaffolds, tissue, 3d cell-derived matrices, Adipose mesenchymal stem cells, Cytotoxicity assay, Extracellular microenvironment, Macromolecular crowders, Mesenchymal stem-cells, Microcarriers
Roki N, Solomon M, Casta L, Bowers J, Getts RC, Muro S, (2021). A method to improve quantitative radiotracing-based analysis of the in vivo biodistribution of drug carriers Bioeng Transl Med 6,
© 2020 The Authors. Bioengineering & Translational Medicine published by Wiley Periodicals LLC on behalf of The American Institute of Chemical Engineers. Biodistribution studies are essential in drug carrier design and translation, and radiotracing provides a sensitive quantitation for this purpose. Yet, for biodegradable formulations, small amounts of free-label signal may arise prior to or immediately after injection in animal models, causing potentially confounding biodistribution results. In this study, we refined a method to overcome this obstacle. First, we verified free signal generation in animal samples and then, mimicking it in a controllable setting, we injected mice intravenously with a radiolabeled drug carrier formulation (125I-antibody/3DNA) containing a known amount of free radiolabel (125I), or free 125I alone as a control. Corrected biodistribution data were obtained by separating the free radiolabel from blood and organs postmortem, using trichloroacetic acid precipitation, and subtracting the confounding signal from each tissue measurement. Control free 125I-radiolabel was detected at ≥85% accuracy in blood and tissues, validating the method. It biodistributed very heterogeneously among organs (0.6–39 %ID/g), indicating that any free 125I generated in the body or present in an injected formulation cannot be simply corrected to the free-label fraction in the original preparation, but the free label must be empirically measured in each organ. Application of this method to the biodistribution of 125I-antibody/3DNA, including formulations directed to endothelial target ICAM-1, showed accurate classification of free 125I species in blood and tissues. In addition, this technique rendered data on the in vivo degradation of the traced agents over time. Thus, this is a valuable technique to obtain accurate measurements of biodistribution using 125I and possibly other radiotracers.
JTD Keywords: biodistribution data correction, degradation, drug delivery carriers, free label, in vivo biodistribution, radiotracing, trichloroacetic acid precipitation, Biodistribution data correction, Degradation, Drug delivery carriers, Free label, In vivo biodistribution, Radiotracing, Trichloroacetic acid precipitation
Rubi-Sans, G, Cano-Torres, I, Perez-Amodio, S, Blanco-Fernandez, B, Mateos-Timoneda, MA, Engel, E, (2021). Development and Angiogenic Potential of Cell-Derived Microtissues Using Microcarrier-Template Biomedicines 9,
Tissue engineering and regenerative medicine approaches use biomaterials in combination with cells to regenerate lost functions of tissues and organs to prevent organ transplantation. However, most of the current strategies fail in mimicking the tissue's extracellular matrix properties. In order to mimic native tissue conditions, we developed cell-derived matrix (CDM) microtissues (MT). Our methodology uses poly-lactic acid (PLA) and Cultispher(R) S microcarriers' (MCs') as scaffold templates, which are seeded with rat bone marrow mesenchymal stem cells (rBM-MSCs). The scaffold template allows cells to generate an extracellular matrix, which is then extracted for downstream use. The newly formed CDM provides cells with a complex physical (MT architecture) and biochemical (deposited ECM proteins) environment, also showing spontaneous angiogenic potential. Our results suggest that MTs generated from the combination of these two MCs (mixed MTs) are excellent candidates for tissue vascularization. Overall, this study provides a methodology for in-house fabrication of microtissues with angiogenic potential for downstream use in various tissue regenerative strategies.
JTD Keywords: angiogenesis, cell-derived matrix, cultispher® s, microtissue, poly-lactic acid microcarriers, Angiogenesis, Cell-derived matrix, Cultispher (r) s, Microtissue, Poly-lactic acid microcarriers, Rat bone marrow mesenchymal stem cells
Manthe, Rachel L., Loeck, Maximilian, Bhowmick, Tridib, Solomon, Melani, Muro, Silvia, (2020). Intertwined mechanisms define transport of anti-ICAM nanocarriers across the endothelium and brain delivery of a therapeutic enzyme Journal of Controlled Release 324, 181-193
The interaction of drug delivery systems with tissues is key for their application. An example is drug carriers targeted to endothelial barriers, which can be transported to intra-endothelial compartments (lysosomes) or transcellularly released at the tissue side (transcytosis). Although carrier targeting valency influences this process, the mechanism is unknown. We studied this using polymer nanocarriers (NCs) targeted to intercellular adhesion molecule-1 (ICAM-1), an endothelial-surface glycoprotein whose expression is increased in pathologies characterized by inflammation. A bell-shaped relationship was found between NC targeting valency and the rate of transcytosis, where high and low NC valencies rendered less efficient transcytosis rates than an intermediate valency formulation. In contrast, an inverted bell-shape relationship was found for NC valency and lysosomal trafficking rates. Data suggested a model where NC valency plays an opposing role in the two sub-processes involved in transcytosis: NC binding-uptake depended directly on valency and exocytosis-detachment was inversely related to this parameter. This is because the greater the avidity of the NC-receptor interaction the more efficient uptake becomes, but NC-receptor detachment post-transport is more compromised. Cleavage of the receptor at the basolateral side of endothelial cells facilitated NC transcytosis, likely by helping NC detachment post-transport. Since transcytosis encompasses both sets of events, the full process finds an optimum at the intersection of these inverted relationships, explaining the bell-shaped behavior. NCs also trafficked to lysosomes from the apical side and, additionally, from the basolateral side in the case of high valency NCs which are slower at detaching from the receptor. This explains the opposite behavior of NC valency for transcytosis vs. lysosomal transport. Anti-ICAM NCs were verified to traffic into the brain after intravenous injection in mice, and both cellular and in vivo data showed that intermediate valency NCs resulted in higher delivery of a therapeutic enzyme, acid sphingomyelinase, required for types A and B Niemann-Pick disease.
JTD Keywords: Blood-brain barrier, ICAM-1-targeted nanocarriers, Targeting valency, Receptor-mediated transport, Lysosomal transcytosis destinations
Llopis-Lorente, A., García-Fernández, A., Murillo-Cremaes, N., Hortelão, A. C., Patinño, T., Villalonga, R., Sancenón, F., Martínez-Máñer, R., Sánchez, S., (2019). Enzyme-powered gated mesoporous silica nanomotors for on-command intracellular payload delivery ACS Nano 13, (10), 12171-12183
The introduction of stimuli-responsive cargo release capabilities on self-propelled micro- and nanomotors holds enormous potential in a number of applications in the biomedical field. Herein, we report the preparation of mesoporous silica nanoparticles gated with pH-responsive supramolecular nanovalves and equipped with urease enzymes which act as chemical engines to power the nanomotors. The nanoparticles are loaded with different cargo molecules ([Ru(bpy)3]Cl2 (bpy = 2,2′-bipyridine) or doxorubicin), grafted with benzimidazole groups on the outer surface, and capped by the formation of inclusion complexes between benzimidazole and cyclodextrin-modified urease. The nanomotor exhibits enhanced Brownian motion in the presence of urea. Moreover, no cargo is released at neutral pH, even in the presence of the biofuel urea, due to the blockage of the pores by the bulky benzimidazole:cyclodextrin-urease caps. Cargo delivery is only triggered on-command at acidic pH due to the protonation of benzimidazole groups, the dethreading of the supramolecular nanovalves, and the subsequent uncapping of the nanoparticles. Studies with HeLa cells indicate that the presence of biofuel urea enhances nanoparticle internalization and both [Ru(bpy)3]Cl2 or doxorubicin intracellular release due to the acidity of lysosomal compartments. Gated enzyme-powered nanomotors shown here display some of the requirements for ideal drug delivery carriers such as the capacity to self-propel and the ability to “sense” the environment and deliver the payload on demand in response to predefined stimuli.
JTD Keywords: Controlled release, Drug delivery, Enzymatic catalysis, Gatekeepers, Nanocarriers, Nanomotors, Stimuli-responsive nanomaterials
Muro, Silvia, (2018). Alterations in cellular processes involving vesicular trafficking and implications in drug delivery Biomimetics 3, (3), 19
Endocytosis and vesicular trafficking are cellular processes that regulate numerous functions required to sustain life. From a translational perspective, they offer avenues to improve the access of therapeutic drugs across cellular barriers that separate body compartments and into diseased cells. However, the fact that many factors have the potential to alter these routes, impacting our ability to effectively exploit them, is often overlooked. Altered vesicular transport may arise from the molecular defects underlying the pathological syndrome which we aim to treat, the activity of the drugs being used, or side effects derived from the drug carriers employed. In addition, most cellular models currently available do not properly reflect key physiological parameters of the biological environment in the body, hindering translational progress. This article offers a critical overview of these topics, discussing current achievements, limitations and future perspectives on the use of vesicular transport for drug delivery applications.
JTD Keywords: Cellular vesicles, Vesicle fusion, Fission and intracellular trafficking, Drug delivery systems and nanomedicines, Transcytosis and endocytosis of drugs carriers, Disease effects on vesicular trafficking, Drug effects on vesicular trafficking, Role of the biological environment
Urbán, P., Valle-Delgado, J. J., Mauro, N., Marques, J., Manfredi, A., Rottmann, M., Ranucci, E., Ferruti, P., Fernàndez-Busquets, X., (2014). Use of poly(amidoamine) drug conjugates for the delivery of antimalarials to Plasmodium Journal of Controlled Release 177, (1), 84-95
Current malaria therapeutics demands strategies able to selectively deliver drugs to Plasmodium-infected red blood cells (pRBCs) in order to limit the appearance of parasite resistance. Here, the poly(amidoamines) AGMA1 and ISA23 have been explored for the delivery of antimalarial drugs to pRBCs. AGMA1 has antimalarial activity per se as shown by its inhibition of the in vitrogrowth of Plasmodium falciparum, with an IC50 of 13.7 μM. Fluorescence-assisted cell sorting data and confocal fluorescence microscopy and transmission electron microscopy images indicate that both polymers exhibit preferential binding to and internalization into pRBCs versus RBCs, and subcellular targeting to the parasite itself in widely diverging species such as P. falciparum and Plasmodium yoelii, infecting humans and mice, respectively. AGMA1 and ISA23 polymers with hydrodynamic radii around 7 nm show a high loading capacity for the antimalarial drugs primaquine and chloroquine, with the final conjugate containing from 14.2% to 32.9% (w/w) active principle. Intraperitoneal administration of 0.8 mg/kg chloroquine as either AGMA1 or ISA23 salts cured P. yoelii–infected mice, whereas control animals treated with twice as much free drug did not survive. These polymers combining into a single chemical structure drug carrying capacity, low unspecific toxicity, high biodegradability and selective internalization into pRBCs, but not in healthy erythrocytes for human and rodent malarias, may be regarded as promising candidates deserving to enter the antimalarial therapeutic arena.
JTD Keywords: Malaria, Nanomedicine, Plasmodium, Polyamidoamines, Polymer-drug carriers, Targeted drug delivery
Ginebra, M. P., Espanol, M., Montufar, E. B., Perez, R. A., Mestres, G., (2010). New processing approaches in calcium phosphate cements and their applications in regenerative medicine Acta Biomaterialia 6, (8), 2863-2873
The key feature of calcium phosphate cements (CPCs) lies in the setting reaction triggered by mixing one or more solid calcium phosphate salts with an aqueous solution. Upon mixture, the reaction takes place through a dissolution-precipitation process which is macroscopically observed by a gradual hardening of the cement paste. The precipitation of hydroxyapatite nanocrystals at body or room temperature, and the fact that those materials can be used as self-setting pastes, have for many years been the most attractive features of CPCs. However, the need to develop materials able to sustain bone tissue ingrowth and be capable of delivering drugs and bioactive molecules, together with the continuous requirement from surgeons to develop more easily handling cements, has pushed the development of new processing routes that can accommodate all these requirements, taking advantage of the possibility of manipulating the self-setting CPC paste. It is the goal of this paper to provide a brief overview of the new processing developments in the area of CPCs and to identify the most significant achievements.
JTD Keywords: Bone regeneration, Calcium phosphate cements, Granules, Microcarriers, Scaffolds
Errachid, A., Mills, C. A., Pla, M., Lopez, M. J., Villanueva, G., Bausells, J., Crespo, E., Teixidor, F., Samitier, J., (2008). Focused ion beam production of nanoelectrode arrays Materials Science & Engineering C 5th Maghreb/Europe Meeting on Materials and Their Applications for Devices and Physical, Chemical and Biological Sensors (MADICA 2006) (ed. -----), Elsevier Science (Mahdia, Tunisia) 28, (5-6), 777-780
We present a method for the production of nanoelectrodes using focussed ion beam techniques (FIB). The electrodes utilise nanometric holes milled in a silicon nitride based pasivation layer, followed by wet etching of a silicon oxide based pasivation layer, to expose an underlying gold electrode. After functionalisation using a surface assembled monolayer and an electrochemically grown polypyrrole, these gold nanoelectrodes have been tested, via cyclic voltammetry, in the detection of [Fe(CN)(6)](4-/3-) ions. The nanoelectrodes will be used to investigate the electrical properties of nanometric biological specimen.
JTD Keywords: Neutral carrier, Solid contact, Microelectrodes, Immobilization