Photochemically crosslinked matrices of gelatin and fibrinogen promote rapid cell proliferation.

Here we report the use of a facile photochemical crosslinking method to fabricate stable polymer matrices from unmodified gelatin and fibrinogen. Gels were produced by covalent crosslinking of the proteins in a rapid photo-oxidative process, catalysed by a ruthenium metal complex and irradiation with visible light. For generation of macroporous, spongy matrices, the proteins and crosslinking reagents were mixed with catalase and hydrogen peroxide to achieve a foaming reaction, producing a stable, foamed matrix that was subsequently photo-crosslinked. C2C12 cells were either seeded onto the matrices after photo-curing or embedded in the protein matrix prior to foaming and crosslinking. Cells seeded onto scaffolds post-curing showed high cell viability and rapid proliferation in vitro. For cells embedded in the matrix prior to crosslinking there was some loss of initial viability, but surviving cells were able to proliferate after a period of in vitro cultivation. The matrices were shown to be biocompatible when implanted into nude mice, with evidence of proliferation and differentiation of cells seeded into the scaffolds. The results are promising for further development of tissue-engineering scaffolds based on this ruthenium-catalysed photo-crosslinking method.