Persistent adhesion of epithelial tissue is sensitive to polymer topography

The persistent adhesion of corneal epithelial tissue to the surface of a po rous polymer is of interest in the development of a corneal onlay. Using an in vitro model system, this study examined the effect of polymer surface t opography on the assembly of basement membrane and hemidesmosomes. Corneal epithelial tissue was grown on polycarbonate surfaces with a range of pore sizes (0.1-3.0 micron, pore diameter) and an equivalent nonporous surface. The ultrastructure of the tissue-polymer interface was evaluated using elec tron microscopy. On the porous surfaces, the tissue responded to a balance between the size of the discontinuity (pores) and the amount of polymer sur face between the pores. Continuous basement membrane and a regular pattern of hemidesmosomal plaque occurred only on the 0.1 micron surface, where bot h the pores and the total surface area covered by pores were relatively sma ll. The assembly of adhesive structures on surfaces with pore diameters bet ween 0.4-2.0 microns was restricted to regions of polymer between pores. No adhesive structures assembled on the nonporous or on the 3.0-micron surfac e. These results demonstrate that, in addition to porosity, surface topogra phy is a significant factor in the formation of structures involved in the persistent adhesion of stratified epithelial tissue on a polymer. (C) 1999 John Wiley & Sons, inc.