by Keyword: Patterns

Matejčić, Marija, Trepat, Xavier, (2023). Mechanobiological approaches to synthetic morphogenesis: learning by building Trends In Cell Biology 33, 95-111

Tissue morphogenesis occurs in a complex physicochemical microenvironment with limited experimental accessibility. This often prevents a clear identification of the processes that govern the formation of a given functional shape. By applying state-of-the-art methods to minimal tissue systems, synthetic morphogenesis aims to engineer the discrete events that are necessary and sufficient to build specific tissue shapes. Here, we review recent advances in synthetic morphogenesis, highlighting how a combination of microfabrication and mechanobiology is fostering our understanding of how tissues are built.Copyright © 2022 Elsevier Ltd. All rights reserved.

JTD Keywords: cell dynamics, elongation, endothelial-cells, epithelium, growth, lumen, mechanical tension, patterns, self-organization, synthetic morphogenesis, tissue folding, tissue mechanics, topological defects, Stem-cells, Tissue shape

Martínez-Miguel M, Castellote-Borrell M, Köber M, Kyvik AR, Tomsen-Melero J, Vargas-Nadal G, Muñoz J, Pulido D, Cristóbal-Lecina E, Passemard S, Royo M, Mas-Torrent M, Veciana J, Giannotti MI, Guasch J, Ventosa N, Ratera I, (2022). Hierarchical Quatsome-RGD Nanoarchitectonic Surfaces for Enhanced Integrin-Mediated Cell Adhesion Acs Applied Materials & Interfaces 14, 48179-48193

The synthesis and study of the tripeptide Arg-Gly-Asp (RGD), the binding site of different extracellular matrix proteins, e.g., fibronectin and vitronectin, has allowed the production of a wide range of cell adhesive surfaces. Although the surface density and spacing of the RGD peptide at the nanoscale have already shown a significant influence on cell adhesion, the impact of its hierarchical nanostructure is still rather unexplored. Accordingly, a versatile colloidal system named quatsomes, based on fluid nanovesicles formed by the self-assembling of cholesterol and surfactant molecules, has been devised as a novel template to achieve hierarchical nanostructures of the RGD peptide. To this end, RGD was anchored on the vesicle's fluid membrane of quatsomes, and the RGD-functionalized nanovesicles were covalently anchored to planar gold surfaces, forming a state of quasi-suspension, through a long poly(ethylene glycol) (PEG) chain with a thiol termination. An underlying self-assembled monolayer (SAM) of a shorter PEG was introduced for vesicle stabilization and to avoid unspecific cell adhesion. In comparison with substrates featuring a homogeneous distribution of RGD peptides, the resulting hierarchical nanoarchitectonic dramatically enhanced cell adhesion, despite lower overall RGD molecules on the surface. The new versatile platform was thoroughly characterized using a multitechnique approach, proving its enhanced performance. These findings open new methods for the hierarchical immobilization of biomolecules on surfaces using quatsomes as a robust and novel tissue engineering strategy.

JTD Keywords: activation, arg-gly-asp (rgd), cell adhesion, extracellular-matrix, growth, integrins, ligands, nanopatterns, quatsomes, scaffolds, self-assembled monolayers, surface engineering, tissue engineering, Arg-gly-asp (rgd), Cell adhesion, Integrins, Nano-structured surfaces, Nanovesicles, Quatsomes, Self-assembled monolayers, Surface engineering, Tissue engineering

Casanellas I, Samitier J, Lagunas A, (2022). Recent advances in engineering nanotopographic substrates for cell studies Frontiers In Bioengineering And Biotechnology 10, 1002967

Cells sense their environment through the cell membrane receptors. Interaction with extracellular ligands induces receptor clustering at the nanoscale, assembly of the signaling complexes in the cytosol and activation of downstream signaling pathways, regulating cell response. Nanoclusters of receptors can be further organized hierarchically in the cell membrane at the meso- and micro-levels to exert different biological functions. To study and guide cell response, cell culture substrates have been engineered with features that can interact with the cells at different scales, eliciting controlled cell responses. In particular, nanoscale features of 1-100 nm in size allow direct interaction between the material and single cell receptors and their nanoclusters. Since the first "contact guidance" experiments on parallel microstructures, many other studies followed with increasing feature resolution and biological complexity. Here we present an overview of the advances in the field summarizing the biological scenario, substrate fabrication techniques and applications, highlighting the most recent developments.Copyright © 2022 Casanellas, Samitier and Lagunas.

JTD Keywords: cell response, density, differentiation, lithography, micro, nanofabrication, nanopatterning, nanopatterns, nanoscale, nanotopography, organization, photolithography, Cell response, Nanofabrication, Nanopatterning, Nanotopography, Plasma-membrane, Receptor nanoclustering

Wagner, AM, Eto, H, Joseph, A, Kohyama, S, Haraszti, T, Zamora, RA, Vorobii, M, Giannotti, MI, Schwille, P, Rodriguez-Emmenegger, C, (2022). Dendrimersome Synthetic Cells Harbor Cell Division Machinery of Bacteria Advanced Materials 34, e2202364

The integration of active cell machinery with synthetic building blocks is the bridge toward developing synthetic cells with biological functions and beyond. Self-replication is one of the most important tasks of living systems, and various complex machineries exist to execute it. In Escherichia coli, a contractile division ring is positioned to mid-cell by concentration oscillations of self-organizing proteins (MinCDE), where it severs membrane and cell wall. So far, the reconstitution of any cell division machinery has exclusively been tied to liposomes. Here, the reconstitution of a rudimentary bacterial divisome in fully synthetic bicomponent dendrimersomes is shown. By tuning the membrane composition, the interaction of biological machinery with synthetic membranes can be tailored to reproduce its dynamic behavior. This constitutes an important breakthrough in the assembly of synthetic cells with biological elements, as tuning of membrane-divisome interactions is the key to engineering emergent biological behavior from the bottom-up.

JTD Keywords: bacterial cell division, bottom-up synthetic biology, dendrimersomes, dynamic min patterns, ftsz assembly, Bacterial cell division, Bottom-up synthetic biology, Dendrimersomes, Dynamic min patterns, Dynamics, Ftsz assembly, Ftsz filaments, Mind, Organization, Pole oscillation, Polymersome membranes, Proteins, Rapid pole, Synthetic cells, Vesicles

Barbero-Castillo A, Riefolo F, Matera C, Caldas-Martínez S, Mateos-Aparicio P, Weinert JF, Garrido-Charles A, Claro E, Sanchez-Vives MV, Gorostiza P, (2021). Control of Brain State Transitions with a Photoswitchable Muscarinic Agonist Advanced Science 8, e2005027

The ability to control neural activity is essential for research not only in basic neuroscience, as spatiotemporal control of activity is a fundamental experimental tool, but also in clinical neurology for therapeutic brain interventions. Transcranial-magnetic, ultrasound, and alternating/direct current (AC/DC) stimulation are some available means of spatiotemporal controlled neuromodulation. There is also light-mediated control, such as optogenetics, which has revolutionized neuroscience research, yet its clinical translation is hampered by the need for gene manipulation. As a drug-based light-mediated control, the effect of a photoswitchable muscarinic agonist (Phthalimide-Azo-Iper (PAI)) on a brain network is evaluated in this study. First, the conditions to manipulate M2 muscarinic receptors with light in the experimental setup are determined. Next, physiological synchronous emergent cortical activity consisting of slow oscillations-as in slow wave sleep-is transformed into a higher frequency pattern in the cerebral cortex, both in vitro and in vivo, as a consequence of PAI activation with light. These results open the way to study cholinergic neuromodulation and to control spatiotemporal patterns of activity in different brain states, their transitions, and their links to cognition and behavior. The approach can be applied to different organisms and does not require genetic manipulation, which would make it translational to humans.

JTD Keywords: brain states, light-mediated control, muscarinic acetylcholine receptors, neuromodulation, Activation, Alternating/direct currents, Basal forebrain, Brain, Brain states, Clinical research, Clinical translation, Controlled drug delivery, Cortex, Forebrain cholinergic system, Genetic manipulations, Higher frequencies, Hz oscillation, Light‐, Light-mediated control, Mediated control, Muscarinic acetylcholine receptors, Muscarinic agonists, Muscarinic receptor, Neurology, Neuromodulation, Neurons, Noradrenergic modulation, Parvalbumin-positive interneurons, Photopharmacology, Receptor-binding, Slow, Spatiotemporal control, Spatiotemporal patterns

Giraldo, B. F., Tellez, J. P., Herrera, S., Benito, S., (2013). Analysis of heart rate variability in elderly patients with chronic heart failure during periodic breathing CinC 2013 Computing in Cardiology Conference (CinC) , IEEE (Zaragoza, Spain) , 991-994

Assessment of the dynamic interactions between cardiovascular signals can provide valuable information that improves the understanding of cardiovascular control. Heart rate variability (HRV) analysis is known to provide information about the autonomic heart rate modulation mechanism. Using the HRV signal, we aimed to obtain parameters for classifying patients with and without chronic heart failure (CHF), and with periodic breathing (PB), non-periodic breathing (nPB), and Cheyne-Stokes respiration (CSR) patterns. An electrocardiogram (ECG) and a respiratory flow signal were recorded in 36 elderly patients: 18 patients with CHF and 18 patients without CHF. According to the clinical criteria, the patients were classified into the follow groups: 19 patients with nPB pattern, 7 with PB pattern, 4 with Cheyne-Stokes respiration (CSR), and 6 non-classified patients (problems with respiratory signal). From the HRV signal, parameters in the time and frequency domain were calculated. Frequency domain parameters were the most discriminant in comparisons of patients with and without CHF: PTot (p = 0.02), PLF (p = 0.022) and fpHF (p = 0.021). For the comparison of the nPB vs. CSR patients groups, the best parameters were RMSSD (p = 0.028) and SDSD (p = 0.028). Therefore, the parameters appear to be suitable for enhanced diagnosis of decompensated CHF patients and the possibility of developed periodic breathing and a CSR pattern.

JTD Keywords: cardiovascular system, diseases, electrocardiography, frequency-domain analysis, geriatrics, medical signal processing, patient diagnosis, pneumodynamics, signal classification, Cheyne-Stokes respiration patterns, ECG, autonomic heart rate modulation mechanism, cardiovascular control, cardiovascular signals, chronic heart failure, decompensated CHF patients, dynamic interaction assessment, elderly patients, electrocardiogram, enhanced diagnosis, frequency domain parameters, heart rate variability analysis, patient classification, periodic breathing, respiratory flow signal recording, Electrocardiography, Frequency modulation, Frequency-domain analysis, Heart rate variability, Senior citizens, Standards

Pla, M., Fernandez, Javier G., Mills, C. A., Martinez, E., Samitier, J., (2007). Micro/nanopatterning of proteins via contact printing using high aspect ratio PMMA stamps and NanoImprint apparatus Langmuir 23, (16), 8614-8618

Micro- and nanoscale protein patterns have been produced via a new contact printing method using a nanoimprint lithography apparatus. The main novelty of the technique is the use of poly(methyl methacrylate) (PMMA) instead of the commonly used poly(dimethylsiloxane) (PDMS) stamps. This avoids printing problems due to roof collapse, which limits the usable aspect ratio in microcontact printing to 10:1. The rigidity of the PMMA allows protein patterning using stamps with very high aspect ratios, up to 300 in this case. Conformal contact between the stamp and the substrate is achieved because of the homogeneous pressure applied via the nanoimprint lithography instrument, and it has allowed us to print lines of protein similar to 150 nm wide, at a 400 nm period. This technique, therefore, provides an excellent method for the direct printing of high-density sub-micrometer scale patterns, or, alternatively, micro-/nanopatterns spaced at large distances. The controlled production of these protein patterns is a key factor in biomedical applications such as cell-surface interaction experiments and tissue engineering.

JTD Keywords: Soft lithography, Cell-adhesion, Microstructures, Fabrication, Stability, Patterns