Rapid isothermal substrate microfabrication of a biocompatible thermoplastic elastomer for cellular contact guidance.

The use of microstructured substrates to study and influence cell orientation, which plays an important role in tissue functionality, has been of great interest lately. Silicon and poly(dimethylsiloxane) substrates have typically been used, but long processing times and exogenous protein surface coating, required to enhance cell viability, limit their use as large-scale platforms. There is thus a need for a non-biodegradable biocompatible substrate that allows rapid and low cost microfabrication. In this paper a styrene-(ethylene/butylene)-styrene block co-polymer (SEBS) microstructured by a rapid replication technique using low pressure an isothermal hot embossing approach has been demonstrated. SEBS substrates were treated with oxygen plasma to enhance cell adhesion and sterilized using ethylene oxide gas. While cell adhesion to and proliferation on these substrates was as good as on tissue culture polystyrene, cellular alignment on microstructured SEBS was also very high (97.7±0.5%) when calculated within a 10° angle variation from the longitudinal axis. Furthermore, tissue sheets on microstructured SEBS have been produced and exhibited cellular alignment within the engineered tissue. In addition, these results were obtained without coating the material with exogenous proteins. Such substrates should be helpful in the culture of tissue engineered substitutes with an intrinsic orientation and to elucidate questions in cell biology.