A spin-coated thermoresponsive substrate for rapid cell sheet detachment and its applications in cardiac tissue engineering

A modular approach to create organized tissue that has gained much attention since the introduction of thermoresponsive surfaces is the assembly of cell sheets. With a change in temperature of grafted poly-N-isopropylacrylamide (pNIPAAm), a thermoresponsive polymer, cell sheets can be harvested with their deposited extracellular matrix (ECM) intact. PNIPAAm has been covalently grafted to cell culture substrates by two primary methods: electron beam irradiation and plasma polymerization. Most tissue engineering laboratories have difficulties using these approaches to custom-make their thermoresponsive surface for specific applications due to the complexities of associated procedures and limited access to required equipment (e.g. e-beam). The goal of this study was to develop a simple, cost-effective approach for the creation of thermoresponsive surfaces using commercially available pNIPAAm for cell sheet harvest. Methods to effectively manipulate viable cell sheets (e.g. transfer and stack) were developed. In addition, a study of cell sheet interaction on fibrin gels is presented and analyzed for future cardiac tissue engineering applications.