Biodegradable waterborne polyurethane grafted with gelatin hydrolysate via solvent-free copolymerization for potential porous scaffold material

One potential porous scaffold material based on polyester waterborne polyurethane (PEUR) grafted with modified gelatin hydrolysate (GH) has been investigated in this research. First, the GH was modified with a silane coupling agent (KH550), and then the modified GH was mixed with pre-polymer emulsion of PEUR to obtain the PEUR grafted GH emulsion (PEUR-g-GH). The synthesized PEUR-g-GH emulsions were characterized by stability analysis and viscosity test. Moreover, the film-forming property of PEUR-g-GH has also been studied, and the PEUR-g-GH films were characterized regarding the water resistance, solvent resistance, mechanical properties, FTIR, AFM, SEM, DMA, TGA and contact angle testing. Finally, the bioactivity and biodegradation were investigated by soaking PEUR-g-GH scaffolds in simulated body fluid (SBF). The results indicated that the PEUR-g-GH emulsion has good stability, water resisting (the contact angle was over 90^o), the PEUR-g-GH showed excellent film-forming, high storage modulus, good structural homogeneity and thermal stability (the temperature of maximum weight loss was over 350 °C). The freeze-dried sample showed porous structure, and the mutual crosslinking of layers can contribute to a good bearing capacity for scaffold. The SBF biodegradability revealed that the biodegradation rate and degree of films gradually increased with the content of GH increased. In addition, the cells on the material were markedly enhanced, and most of cells have proliferated and formed vesicles, which shown a good biocompatibility.