Matrix-metalloproteinase and photosensitive peptide units are combined with heparin and poly(ethylene glycol) into a light-sensitive multicomponent hydrogel material. Localized degradation of the hydrogel matrix allows the creation of defined spatial constraints and adhesive patterning for cells grown in culture. Using this matrix system, it is demonstrated that the degree of confinement determines the fate of neural precursor cells in vitro.
Micropatterned surfaces with cell adhesive areas, delimited by protein repellent microstructures, are in high demand for its potential use as relevant biological assays. This is not only because such surfaces allow directing cell growth in a spatially localized and restricted manner, but also because they can be used to elucidate basic cell growth and orientation mechanisms. Here, it is presented a laser-assisted micropatterning technique to fabricate large area microstructures of poly (ethylene glycol) hydrogel onto a cell adhesive surface: a biofunctional maleic anhydride copolymer. By varying photoinitiator, laser intensity, copolymer as well as the hydrogel layer thickness, the optimum conditions to produce high quality features were found. The suitability of these micropatterned substrates for bioassay applications was proved by cell adhesion studies. The introduced procedure could be used to prepare a broad range of microarrays for certain bioanalytical approaches and to create different types of biofunctional surfaces.
Periodic microstructures in styrene-acrylonitrile (SAN) copolymers are fabricated by two-beam direct laser interference patterning using a nanosecond pulsed laser operating at a wavelength of 266 nm. The SAN copolymers are synthesized using different molar ratios (styrene to acrylonitrile) by a free radical polymerization process. The chemical composition of the copolymers and their properties are determined using Fourier transformed infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Depending on the composition of the irradiated copolymer films, with weight ratios ranging from 58 to 96.5% of styrene to acrylonitrile, different ablation behaviors are observed. The laser fluence necessary to locally ablate the copolymer is found to be dependent on the copolymer composition. Unlike other dielectric polymers, the laser irradiation produced both direct ablation of the irradiated material and collapse of the surface. It is shown that, by varying the laser fluence and the copolymer composition, the surface structure can be changed from a periodic pattern with a swelled topography to an ablated-like structure. The number of holes does not depend monotonically on the amount of PS or PAN units but shows a more complex behavior which depends on the copolymer composition and the laser fluence.
In this study, a mask-less laser-assisted patterning method is used to fabricate welldefined cell-adhesive microdomains delimited by protein-repellent poly(ethylene glycol) (PEG) microstructures prepared from multiarm (8-PEG) macromonomers. The response of murine fibroblasts (L-929) toward these microdomains is investigated, revealing effective cell confinement within the celladhesive areas surrounded by nonadhesive 8-PEG microstructures. Moreover, the spatial positioning of cells in microdomains of various sizes and geometries is analyzed, indicating control of cell density, size, and elongated cell shape induced by the size of the microdomains and the geometric confinement.
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