Photo-Cross-Linked Porous Hybrid Networks Based on Insoluble Collagen and Poly(trimethylene carbonate)

Porous hybrid networks were formed from methacrylated collagen (ICol-MA) fibrils and methacrylated PTMC (PTMC-tMA). Dispersing ICol-MA and dissolving PTMC-tMA in DMSO acidified with HCl (DMSO/HCl), followed by mixing, casting, freezing, photo-cross-linking, and solvent extraction, resulted in networks with high porosities and gel contents. ATR-FTIR showed that hybrid networks had compositions similar to the mixture compositions prior to photo-cross-linking. Mechanical testing of porous hybrid networks, in particular the ICol-MA:PTMC-tMA 17:83 wt % network, showed improved mechanical properties compared to non-cross-linked ICol and ICol-MA networks prepared in DMSO/HCl. Additionally, cross-linking alone already improves the properties of porous collagen structures. Interestingly, photo-cross-linking ICol-MA in acetic acid solution resulted in the best mechanical properties, suggesting that the solvent affects collagen fibril structure and thus network mechanical properties. Indeed, acetic acid does not alter the collagen banding structure, whereas DMSO/HCl does. Thus, further investigation into the effect of the solvent on the network properties is needed.