Fabrication and characterization of chemically crosslinked keratin films

A film was prepared by casting the reduced keratin solution after mixing with chemical crosslinkers such as ethylene glycol diglycidyl ether (EGDE) and glycerol diglycidyl ether (GDE). Although the keratin without an addition of a plasticizer gave rise to a fragile film, the keratin treated with those crosslinkers gave a tenacious and flexible film similarly to the mixing with chitosan, which we previously reported [Biomaterials 23 (2002) 817]. Chemically crosslinked keratin films stretched longer than keratin–chitosan composite film and showed much improved waterproof characteristics, that is, no swelling was observed under acidic and neutral aqueous conditions and they swelled to a lesser extent under basic condition, although keratin–chitosan composite film significantly swelled in acidic and neutral solution. Chemically crosslinked keratin film as well as keratin–chitosan composite film maintained their mechanical properties upon re-drying after swelling.When mouse fibroblast cells are cultured on crosslinked keratin-coated surface, the attachment of cells is a little delayed compared with the cells on keratin, keratin–chitosan composite and chitosan films. However, the cells once attached to the crosslinked keratin surface well proliferated, suggesting the biocompatibility of chemically crosslinked keratin film.