胶原/聚磺酸基两性电解质IPN水凝胶作为角膜替代物

Our study showed that both temperature and pH can caused a change in the conformation of porcine atelocollagen. The triple helix of collagen was disrupted in an acid and high temperature environment; in particular, heat treatment caused permanent denaturation of collagen. With the collagen conformation compromised, the mechanical properties decreased. This observation provided insight into the design of a collagen-based hydrogel that can be fabricated at low temperature and high pH, given that the collagen is soluble. In a sealed system under an ice-water bath and a pH of 5.5, collagen-polysulfobetaine corneal substitutes were fabricated from an interpenetrating polymer network (IPN) comprised of 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC)/N-hydroxysuccinimide (NHS) crosslinked collagen and cleavable N,N-bis(acryloyl)cystamine (BAC) crosslinked N-(3-(methacryloylamino)propyl)-N,N-dimethyl-N-(3-sulfopropyl) ammonium hydroxide (MPDSAH). White light transmission and refractive indices were measured to show that the optical properties of the resulting hydrogels were comparable or superior to those of human cornea. At optimal ratios, compared to collagen only hydrogels, the IPN hydrogels showed enhanced mechanical properties, and retarded degradation under collagenase digestions. Degradation behavior of IPN hydrogels by dithiothreitol (DTT) demonstrated that a MPDSAH-BAC network could be degraded by reduction in vivo. It was observed that the IPN hydrogels also supported in vitro corneal cell proliferation and nerve growth.