Abstract
Purpose: :
To fabricate biosynthesized transparent acellular membranes with precise corneal curvature by vitrifying type-I collagen hydrogels for corneal stromal reconstruction.
Methods: :
The vitrified type-I collagen membrane with controlled curvature (curved collagen Vitrigel, CCV) was prepared following a three-stage sequence: gelation, vitrification (slow and fast), and rehydration. First, the collagen solution was added onto a contact lens concave mold assembled in a glass chamber with a small opening and gelled at 37 °C and 5% CO2 for 2 h. Second, slow vitrification of the gelled collagen was performed in the assembled mold at 15 °C and 40% relative humidity for 24 h. Fast vitrification of the collagen gel was then carried out in the same incubation condition for two weeks by disassembling the glass chamber from the contact lens concave mold. Third, these CCV membranes were stored at room temperature in the dark until being rehydrated for stromal reconstruction experiments. The integration of the CCV membranes with various dimensions in lamellar corneal pockets was examined using rabbit cadaver eyes. Traditional, flat collagen Vitrigel (FCV) was also prepared and compared with CCV as controls.
Results: :
The newly-developed method of CCV membranes was delicately designed. During preparation, the collagen gel was adhered to the contact lens concave mold and thus reduced only in thickness for approximately 100-fold. In contrast to FCV, the self-supporting capability of the CCV membrane dramatically facilitated the membrane handling compared to the FCV membranes when implanting in cadaveric eyes. Furthermore, direct observation of the CCV implanted in cadaveric eyes and subsequent histological results confirmed that the three-dimensionally shaped CCV membrane matched the corneal contour precisely, allowing extensive host-graft integration over a large area without any wrinkle formation due to unmatched curvature which is often observed with the FCV membrane.
Conclusions: :
We developed a new method to fabricate three-dimensional shaped CCV membranes with critical improvements in handling convenience and corneal integration. These transparent and mechanically robust membranes demonstrated significant potential in corneal stromal reconstruction.
Keywords: cornea: basic science • wound healing • shape and contour