Double thin film-based sandwich-cell carrier design for multicellular tissue engineering

Abstract

Many organs are multicellular and each cell type requires a different microenvironment. Thus, there is a need for modular structures where the microenvironment of each cell type can be tuned separately. Herein, we describe enzymatically crosslinked gelatin based double layered film structures where each layer can be loaded with growth factors separately. As a model, we have developed a bi-layer system to produce a respiratory epithelium. This system constitutes an in vitro “epithelial patch” that can be adhered to the lumen of any implant. Crosslinking of the patches with transglutaminase resulted in 7days of stability at 37°C. The film layer was first used to release growth factors and it was shown that the release significantly improved the proliferation over 5days. A549 human lung epithelial cells were used and under the release of an epithelial growth supplement mix, there was a significant improvement on the epithelial proliferation (p<0.01). The designed substrate was successfully attached to titanium implants and we demonstrated the stability of the epithelial patch under in vitro conditions for 7days without deterioration. Under co-culture conditions for three days both cell types were alive. Such patches can be used to obtain fast epithelialization of large implant surfaces.