Gelatin as scaffold for tissue engineering

he term Cell Sheet Engineering refers to the procedure for which sheet of cells produced on a substrate are used to promote in situ regenerative processes. This method has been implemented by Okano et al. who demonstrated that by using a thermoresponsive polymer substrate, such as poly-N-isopropylacrylamide (PNIPAAm), the formed cell sheet can be easily detached from the substrate just by decreasing the temperature of a few degrees. In this work we have investigated the use of a gelatin hydrogel as substrate for promoting the formation of a cell sheet for cell sheet engineering. The procedure exploits the fact that the used gelatin melts at 37 C, allowing the detachment of the cells cultured below that temperature when gelatin melts. The solution of gelatin (1 : 6 in culture medium) was cast into a culture plate and aged at room temperature, 100% relative humidity for 24 h and then at 29 C, 100% RH for 48 h. After aging, cell culture (MRC5) at 31 C on the gel surface started. In 24 h cells attached to the surface starting to spread, forming a uniform web of cells in 48 h and a confluent layer within one week. This cell sheet was easily transferable, as a print, to any other surface (materials, tissue or organ) kept at 37 C. In our tests, we transferred it to the bottom of a polystyrene Petri dish and verified that cells were viable and active. We also checked the produc- tion of Laminin, Fibronectin and Focal Adhesion Kinase with Confocal Laser Microscopy.