Corneal Substitutes of Protein-loaded Collagen/Polyzwitterion IPN

Collagen/polyzwitterion IPN based corneal substitutes were fabricated by crosslinking porcine type I atelocollagen and N-3-(methacryloylamino) propyl-N,N-dimethyl-N-(3-sulfopropyl) ammonium hydroxide(MPDSAH) with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide/N-hydroxysuccinimide and poly(ethylene glycol) diacrylate(PEGDA) ,respectively.The white light transmission and refractive indices of IPN corneal susbtitutes were similar to those of natural human cornea.IPN hydrogels had superior mechanical properties and collagenase resistance compared to pristine collagen hydrogels.Human corneal epithelia grew well on the surface of IPN hydrogel.Bovine serum albumin(BSA) and nerve growth factor(NGF) were efficiently encapsulated in corneal substitute by freeze-drying and re-swelling,and drug-embedded xerogels could be stored in dry state,avoiding the denaturation and leakage of active factors in wet state.It is expected that the completely shape-recovered corneal subsitutes after re-swelling can be implanted into diseased site.BSA and NGF were found to release from IPN hydrogel in a sustainable manner.NGF-loaded composite corneal substitute shows promise in promoting the regeneration of corneal tissue as well as nerve.