Corneal opacity is a leading cause of blindness. It can be caused due to several complications such as corneal dryness, diabetes, and injuries sustained by the cornea. The function of corneal epithelium, one of the three major layers in the cornea, is to protect the inner regions of the eye. Corneal epithelial cells present a physical barrier to external agents such microorganisms, and harmful 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 a simple and versatile approach to fabricate basal membrane mimics that recapitulate the porosity and topography in vivo. Porous membranes were prepared by the assembly of polyelectrolyte multilayers comprised of anionic poly-acrylic acid and cationic poly-allylamine hydrochloride. Porosity on the nano and micro scale was induced by the protonation of carboxylic acid groups and the subsequent reorganization of the polymers upon immersing the films in solutions whose pH ranged from 1.8-3. The porosity can be tuned and controlled to the desired feature size. The average pore diameter measured by AFM was found to be ~100nm and ~ 600nm for the nanoporous and sub-micron porous films respectively. Immortalized corneal epithelial cells were cultured on the porous substrata. Corneal epithelial cell proliferation and migration speeds were significantly higher on nanoporous films. Corneal epithelial cells cultured on nanoporous surfaces exhibit multiple vinculin focal adhesions and well-defined actin cytoskeletal organization. Polyelectrolyte multilayer surfaces with porosity on the nanoscale offer a new route for the growth of corneal epithelium in vitro by mimicking the nanoscale surface topography of basal membranes found in vivo.

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