Construction and biocompatibility of penetrating corneal transplant substitute with cross-linked acellular porcine cornea and biopolymer polyurethane

Abstract

In this study, acellular porcine cornea (APC) was composited with biopolymer polyurethane (PU), in which Polyethylene glycol (PEG) served as porogen, to fabricate a breathable and impermeable barrier and maintain the transparency of APC. To improve the effect of decellularization on the collagen fibrolamella of the APC, structural regularity and stability as well as postoperative corneal edema and melting, crosslinking was taken as an effective way to improve the mechanical properties and anti-enzymatic hydrolysis of APC. Chemical cross-linking in different agents, crosslink concentrations, and reaction times were conducted. The transparency, elastic modulus, oxygen permeability, crosslinking degree, and expansion thickness were examined. Furthermore, the immunogenicity, cytocompatibility, and histocompatibility of the cross-linked APC-PU composite under the optimal crosslinking parameters (GP-0.2 %-3.0, EDC-1.0 %-1.0, GD-0.8 %-0.3) were analyzed. The results showed that the GD-0.8 %-0.3 samples demonstrated cytotoxicity and significant neovascularization during subcutaneous experiments. Moreover, a proliferation membrane was formed on the PU surface in the orthotopic transplantation, suggesting immune rejection. The GP-0.2 %-3.0 group exhibited pronounced edema and delamination in the 4th week, indicating inadequate permeability and incomplete fiber cross-linking. However, the EDC-1.0 %-1.0 group promoted cell adhesion and proliferation, while maintaining graft integrity without degradation upon subcutaneous implantation. No corneal swelling or degradation was observed within 4 weeks post-transplantation. Cross-linking of EDC/NHS is an effective method for fabricating the ideal and functional APC-PU composite for penetrating keratoplasty.