Recombinant human collagen hydrogels with hierarchically ordered microstructures for corneal stroma regeneration

Tissue engineered scaffolds have demonstrated values in fabricating corneal equivalence. Attempts in this area tend to develop functional scaffold with physiochemical properties and structure resembling the native corneal tissue. Herein, a novel recombinant human collagen (RHC) based scaffold with ordered microstructures is presented to induce the regeneration of corneal stroma. As the RHC is modified with methacrylate anhydride (MA) under optimized concentration and is tailored with hierarchically ordered microstructures of aligned microgrooves and inverse opal nano-scale pores, the derived collagen hydrogels (RHCMA) can possess physiochemical properties resembling native cornea. Diverse topological structures (culture dish, RHCMA hydrogel without patterns, MI-RHCMA hydrogel patch with different width of microgrooves) are determined to study their influence on the growth and differentiation of corneal limbal stromal stem cells (LSSCs), and results demonstrate that the novel MI-RHCMA hydrogel patch could induce LSSCs to grow orderly and differentiate into keratocyte in vitro. Rat intrastromal keratoplasty are performed to examine the tissue repair efficacy of the derived collagen hydrogels, and the results indicate that the novel MI-RHCMA hydrogel patch could induce the regeneration of damaged corneal stroma in vivo. These results indicate that our presented scaffolds can be an effective transplantation graft and will find important values for the damaged cornea in the clinic.