Surface Functionalization of Thiol-Ene Elastomers for Biomaterial Applications

The ability to create substrates that can mimic the extracellular matrix (ECM) surrounding a cell is pivotal in understanding how external cues, such as modulus and topography, affect cellular development.   We have developed a vinyl-rich thiol-ene elastomer which can be readily functionalized with thiol-terminated chemical moieties.  As a demonstration, cysteine-terminated peptides, with an RGDS backbone, are synthesized and chemically attached to this elastomeric substrate via a Michael-type addition under alkaline conditions.  The RGDS backbone facilitates cell adhesion and spreading atop the substrate.  The attachment is characterized using fluorescence microscopy and Nano-IR Spectroscopy.  Previous studies have shown that with the incorporation of a photoinitiator and photoabsorber, this elastomer can form surface wrinkles through free radical photopolymerization of the excess vinyl groups.  Moreover, these wrinkles can be easily tuned, confined and aligned through photomasked light.  Lastly, the modulus of these substrates can be controlled by selecting appropriate combinations of multifunctional thiols and enes, which control the molecular weight between crosslinks.  With a diverse library of thiol and ene monomers and biochemical molecules, we have developed a highly versatile system in which we can control surface topography, surface chemistry and modulus.