(219e) Nanoporous Multilayer Surfaces for the Design of Tissue Engineered Corneal Epithelium

A leading cause of blindness in the world is corneal opacity. It is caused due to several complications e.g. corneal dryness, diabetes, and injuries sustained by the cornea. Corneal epithelial cells present a physical barrier to external agents (e.g. microorganisms, UV radiation) thereby protecting the interior regions of the eye, furthermore, the epithelium plays a significant role during wound healing. In vivo, the corneal epithelium is adhered to a basal membrane that exhibits porosity on the nanoscale. We report the design of basal membrane mimics that recapitulate the porosity and topography in vivo and support the growth of tissue engineered corneal epithelium. Porous membranes were prepared by the assembly of polyelectrolyte multilayers. Porosity on the nano and micro scale was induced by immersing the films in solutions whose pH ranged from 2-3. The average pore diameter was ~ 100nm and ~ 3 µm for the nanoporous and microporous films respectively. Immortalized corneal epithelial cells (immortalized by transfection with the pRSV-T plasmid) were cultured on the porous substrata. Cellular response to porosity and the ability to form stratified epithelium were investigated. Cell proliferation was ~ four-fold higher on nanoporous surfaces compared to microporous surfaces. Corneal epithelial cells exhibited well-defined actin fibers through the entire cross-section of the cell when adhered to a nanoporous surface; in contrast, on a microporous surface the actin concentration was very diffuse and located primarily at the periphery of the cell. Projected cell areas were higher on the nanoporous surfaces and there is evidence of formation of layered epithelium. Polyelectrolyte multilayer surfaces with porosity on the nanoscale offer a new route for the growth of corneal epithelium in vitro by mimicking the porosity and topography of basal membranes in vivo.