A comparison of biological coatings for the promotion of corneal epithelialization of synthetic surface in vivo.

PURPOSE To investigate the effect of a range of biological coatings on corneal epithelialization of a synthetic polymer surface in vivo. METHODS Eight diverse biological factors (collagen I, collagen III, collagen IV, laminin, fibronectin, endothelial extracellular matrix, hyaluronic acid, and chondroitin sulfate) were coated individually onto the surface of polycarbonate membranes with a pore size of 0.1 micro m. The coated membranes were implanted on the anterior cornea of adult cats and were clinically assessed for rapidity and extent of and persistence of epithelial overgrowth. The membranes with persistent epithelial attachment were examined histologically by immunohistochemistry and routine light and electron microscopy. RESULTS Collagen I, collagen IV, and laminin consistently enhanced migration and attachment of corneal epithelial cells in vivo. Multiple-layered epithelium over the collagen I-, collagen IV-, and laminin-coated membranes was demonstrated histologically. The collagen I-coated membranes performed best, in that they showed greater stratification and differentiation of the epithelium. Formation of basement membrane and adhesion complexes over the collagen I-coated membranes was detected by immunohistochemistry and electron microscopy up to 9 weeks after implantation. Membranes coated by fibronectin, endothelial extracellular matrix, hyaluronic acid, and chondroitin sulfate did not support persistent epithelial overgrowth. Compromised biostability of these coatings was mostly likely associated with postsurgical reactions of the host corneal tissue. CONCLUSIONS A biologically modified polymer can support migration and adhesion of corneal epithelial cells in vivo. The collagen I-modified surface exhibited the most promising performance, both clinically and histologically.