by Keyword: Microcontact printing

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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.

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

Credi, C., De Marco, C., Molena, E., Pla Roca, M., Samitier, J., Marques, J., Fernàndez-Busquets, X., Levi, M., Turri, S., (2016). Heparin micropatterning onto fouling-release perfluoropolyether-based polymers via photobiotin activation Colloids and Surfaces B: Biointerfaces 146, 250-259

A simple method for constructing versatile ordered biotin/avidin arrays on UV-curable perfluoropolyethers (PFPEs) is presented. The goal is the realization of a versatile platform where any biotinylated biological ligands can be further linked to the underlying biotin/avidin array. To this end, microcontact arrayer and microcontact printing technologies were developed for photobiotin direct printing on PFPEs. As attested by fluorescence images, we demonstrate that this photoactive form of biotin is capable of grafting onto PFPEs surfaces during irradiation. Bioaffinity conjugation of the biotin/avidin system was subsequently exploited for further self-assembly avidin family proteins onto photobiotin arrays. The excellent fouling release PFPEs surface properties enable performing avidin assembly step simply by arrays incubation without PFPEs surface passivation or chemical modification to avoid unspecific biomolecule adsorption. Finally, as a proof of principle biotinylated heparin was successfully grafted onto photobiotin/avidin arrays.

Keywords: Antifouling, Heparin, Malaria, Microcontact arrayer, Microcontact printing, Micropatterning, Perfluoropolyether, Photobiotin, Polymers, Soft lithography

Vedula, Sri Ram Krishna, Ravasio, Andrea, Anon, Ester, Chen, Tianchi, Peyret, G., Ashraf, Mohammed, Ladoux, Benoit, (2014). Microfabricated environments to study collective cell behaviors Methods in Cell Biology (ed. Piel, M., Théry, M.), Academic Press 120, 235-252

Abstract Coordinated cell movements in epithelial layers are essential for proper tissue morphogenesis and homeostasis. Microfabrication techniques have proven to be very useful for studies of collective cell migration in vitro. In this chapter, we briefly review the use of microfabricated substrates in providing new insights into collective cell behaviors. We first describe the development of micropatterned substrates to study the influence of geometrical constraints on cell migration and coordinated movements. Then, we present an alternative method based on microfabricated pillar substrates to create well-defined gaps within cell sheets and study gap closure. We also provide a discussion that presents possible pitfalls and sheds light onto the important parameters that allow the study of long-term cell culture on substrates of well-defined geometries.

Keywords: Microfabricated substrates, Microcontact printing, Collective cell behavior, Geometrical constraints, Epithelial gap closure

Martínez, E., Pla, M., Samitier, J., (2012). Micro/nanopatterning of proteins using a nanoimprint-based contact printing technique Nanotechnology in Regenerative Medicine - Methods and Protocols (Methods in Molecular Biology) (ed. Navarro, M., Planell, J. A.), Springer (New York, USA) 811, 79-87

Micro and nanoscale protein patterning based on microcontact printing technique on large substrates have often resolution problems due to roof collapse of the poly(dimethylsiloxane) (PDMS) stamps used. Here, we describe a technique that overcomes these issues by using instead a stamp made of poly(methyl methacrylate) (PMMA), a much more rigid polymer that do not collapse even using stamps with very high aspect ratios (up to 300:1). 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 150 nm wide, at a 400 nm period. This technique, therefore, provides an excellent method for the direct printing of high-density submicrometer scale patterns, or, alternatively, micro/nanopatterns spaced at large distances.

Keywords: Microcontact printing, Nanoimprint lithography, Poly(methyl methacrylate), Protein

Caballero, D., Samitier, J., Bausells, J., Errachid, A., (2009). Direct patterning of anti-human serum albumin antibodies on aldehyde-terminated silicon nitride surfaces for HSA protein detection Small 5, (13), 1531-1534

Silicon nitride surfaces are modified with a triethoxysilane aldehyde self-assembled monolayer for the direct immobilization of monoclonal antibodies and the detection of human serum albumin proteins, without any activation requirements. Surface modification and the specific recognition interaction between the HSA protein and its associated antibody are studied by fluorescence microscopy and atomic force microscopy.

Keywords: Aldehyde, Human serum albumin, Immunosensors, Microcontact printing, Silicon nitride

Diez-Ahedo, Ruth , Normanno, Davide , Esteban, Olga,, Bakker, Gert-Jan, Figdor, Carl, Cambi, Alessandra , Garcia-Parajo, M. F., (2009). Dynamic re-organization of individual adhesion nanoclusters in living cells by ligand-patterned surfaces Small 5, (11), 1258-1263

Ligand-patterned surfaces alter the spatio-temporal organization of specific receptors on the cell membrane. Chemically confined surfaces are fabricated using microcontact patterning. The dynamic re-organization of the integrin LFA-1 in living cells is monitored at the single-molecule level using total internal reflection fluorescence. The image on the left shows individual LFA-1 nanoclusters on a single cell being recruited to ligand-rich areas of the pattern.

Keywords: Cell adhesion, Microcontact printing, Patterning, Single molecule studies

Martinez, E., Lagunas, A., Mills, C. A., Rodriguez-Segui, S., Estevez, M., Oberhansl, S., Comelles, J., Samitier, J., (2009). Stem cell differentiation by functionalized micro- and nanostructured surfaces Nanomedicine 4, (1), 65-82

New fabrication technologies and, in particular, new nanotechnologies have provided biomaterial and biomedical scientists with enormous possibilities when designing customized supports and scaffolds with controlled nanoscale topography and chemistry. The main issue now is how to effectively design these components and choose the appropriate combination of structure and chemistry to tailor towards applications as challenging and complex as stem cell differentiation. Occasionally, an incomplete knowledge of the fundamentals of biological differentiation process has hampered this issue. However, the recent technological advances in creating controlled cellular microenvironments can be seen as a powerful tool for furthering fundamental biology studies. This article reviews the main strategies followed to achieve solutions to this challenge, particularly emphasizing the working hypothesis followed by the authors to elucidate the mechanisms behind the observed effects of structured surfaces on cell behavior.

Keywords: Cell pattering, Differentiation, Microcontact printing, Micropatterning, Microstructure, Nanoimprinting, Nanostructure, Stem cells

Sporer, C., Casal, L., Caballero, D., Samitier, J., Errachid, A., Perez-Garcia, L., (2009). Novel anionophores for biosensor applications: nano characterisation of SAMS based on amphiphilic imidazolium protophanes and cyclophanes on gold surfaces Sensor Letters 6th Maghreb-Europe Meeting on Materials and Their Applications for Devices and Physical, Chemical and Biological Sensors , AMER SCIENTIFIC PUBLISHERS (Rabat, Morocco) 7, (5), 757-764

Here we report on the results of surface deposition of the novel amphiphilic imidazolium heterocyclophanes and protophanes 1, 2, 3 onto gold electrodes by soft lithography and wet chemistry techniques. Depending on the specific functionalization conditions chosen, the surface properties and the pattern composition can vary widely. The formation of aggregates of monolayers or oligolayer structures and of rings with nano dimensioned wall widths has been investigated with Atomic Force Microscopy (AFM), Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) and Contact angle measurements.

Keywords: Afm, Imidazolium anionophores, Microcontact printing, Tof-sims

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