Fabrication And Research Of The Collagen-based Corneal Repair Material

Corneal disease is the main leading cause of blindness worldwide. Corneal transplantation is the only available treatment currently. However, human donor corneas are extremely tight. The severe shortage of safe, good quality corneal tissues have led to various efforts to develop corneal substitutes. Corneal repair and regeneration brings hope to patients and preparing an ideal material for corneal regeneration is the key. As an ideal corneal regeneration material, it should be transparent, degradable and biocompatible and possess excellent permeability and suitable mechanical property. Although collagen with outstanding biocompatibility has promising application in corneal tissue engineering, the mechanical properties of collagen-based scaffolds, especially suture retention strength, must be further improved to satisfy the requirements of clinical applications. This paper describes a toughness reinforced collagen-based membrane using silk fibroin. The collagen-silk fibroin membranes based on collagen(silk fibroin(w/w) ratios of 100:5, 100:10 and 100:20) were prepared by using silk fibroin and cross-linking by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide(EDC). These membranes were analyzed by scanning electron microscopy(SEM) and their optical property had been tested. The water content was found to be dependent on the content of silk fibroin, and CS10 membrane(loading 10 wt % of silk fibroin) performed the optimal mechanical properties. Also the suture experiments have proved CS10 has high suture retention strength, which can be sutured in rabbit eyes integrally. Moreover, the composite membrane proved good biocompatibility for the proliferation of HCECs(human corneal epithelial cells) in vitro. Lamellar keratoplasty shows that CS10 membrane promoted complete epithelialisation in 35 ± 5 days, and their transparency is restored quickly in the first month. Corneal rejection reaction, neovascularization and keratoconus are not observed. The composite films show potential for use in the field of corneal tissue engineering.UVA/ riboflavin cross-linking was widely used in crosslink corneal collagen for corneal ectatic diseases. In this paper, UVA/ riboflavin cross-linking was developed to fabricate collagen-based cornea repair material. Influence of irradiation intensity and irradiation time on the cross-linking efficiency has been showed. Also the collagen membranes cross-linked by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide(EDC) and with no crosslink had been showed as control. These membranes were analyzed by scanning electron microscopy(SEM). Their optical property and crosslink degree had been tested. Mechanical performance could be due to the crosslink degree of the membranes. Also the stability of membranes was closely related to the crosslinking degree, not only its resistant to Collagenase and thermal stability. Moreover, the membrane crosslinked by UVA/ riboflavin proved good biocompatibility for the proliferation of HCECs(human corneal epithelial cells) in vitro. Lamellar keratoplasty shows that 05 C membrane promoted complete epithelialisation in 28 ± 5 days. Although neovascularization was observed once, their transparency is restored quickly in the first 6 weeks. Corneal rejection reaction and keratoconus are not observed. The membrane crosslinked by UVA/ riboflavin showed potential for use in the field of corneal tissue engineering. It was better to set the irradiation time: 30~45min, irradiation intensity: 3~10m W/cm2 to prepare collagen-based corneal repair material.