Photocurable hybrid hydrogels based on gelatin and polysaccharides for sutureless repair of corneal defects

Corneal transplantation is the prevailing treatment for severe cornea diseases. Considering the shortage of donor tissues and postoperative complications associated with conventional suturing, it is imperative to develop alternative strategies for corneal transplantation. Photocurable hydrogels have attracted considerable attention as corneal substitutes due to their favorable physicochemical properties and application flexibility. However, most photocurable hydrogels focus on repairing focal corneal defects, and still suffer from insufficient mechanical strength and poor adhesion properties. Herein, a photocurable hydrogel GOC composed of gelatin methacryloyl (GelMA), oxidized hyaluronic acid (OHA), and carboxymethyl chitosan (CMCS) is fabricated for sutureless repair of large corneal defects (7 mm). This injectable hydrogel exhibits superior transparency, low swelling rate, tunable mechanical performance, and excellent adhesive properties. In vitro studies demonstrate that GOC hydrogel can support the proliferation and migration of human corneal epithelial cells (HCECs), indicating satisfactory cytocompatibility. Additionally, GOC hydrogel can accurately fill large corneal defects and produce grafts with smooth surfaces. Based on the results of slit-lamp microscopy, AS-OCT, confocal microscopy, and histological evaluations, GOC hydrogel enables effective repair of large corneal defects by facilitating re-epithelialization and stromal reconstruction, and meanwhile reducing inflammatory responses and corneal scarring. Therefore, GOC hydrogel may provide an alternative for sutureless treatment of large corneal defects.