Simultaneous Interpenetrating Polymer Network of Collagen and Hyaluronic Acid as an <i>In Situ</i>-Forming Corneal Defect Filler

Abstract

Timely treatment of corneal injuries injury can help to prevent corneal scarring, blindness, and the need for corneal transplantation. This work describes a novel hydrogel that can fill corneal defects and assist in corneal regeneration. This hydrogel is a simultaneous interpenetrating polymer network (IPN) composed of collagen cross-linked <i>via</i> strain-promoted azide-alkyne cycloaddition reaction and hyaluronic acid cross-linked <i>via</i> thiol-ene Michael click reaction. The formation of the IPN gel was confirmed <i>via</i> FTIR spectra, UV-vis spectra, and morphological changes. We compared the gelation time, mechanical properties, transmittance, and refractive index of the IPN gel to the collagen gel, hyaluronic acid gel, and semi-IPN gel. The IPN combined the advantages of collagen and hyaluronic acid gels and supported corneal epithelial cell growth on its surface. When applied to corneal stromal defects <i>in vivo</i>, the IPN avoided epithelial hyperplasia, decreased stromal myofibroblast formation, and increased tight junction formation in the regenerated epithelium.