The influence of biomimetic topographical features and the extracellular matrix peptide RGD on human corneal epithelial contact guidance.

A major focus in the field of tissue engineering is the regulation of essential cell behaviors through biophysical and biochemical cues from the local extracellular environment. The impact of nanotopographical cues on human corneal epithelial cell (HCEC) contact guidance, proliferation, migration and adhesion have previously been demonstrated. In the current report we have expanded our study of HCEC responses to include both biophysical and controlled biochemical extracellular cues. By exploiting methods for the layer-by-layer coating of substrates with reactive poly(ethylene imine)/poly(2-vinyl-4,4-dimethylazlactone)-based multilayer thin films we have incorporated a single adhesion peptide motif, Arg-Gly-Asp (RGD), on topographically patterned substrates. This strategy eliminates protein adsorption onto the surface, thus decoupling the effects of the HCEC response to topographical cues from adsorbed proteins and soluble media proteins. The direction of cell alignment was dependent on the scale of the topographical cues and, to less of an extent, the culture medium. In EpiLife® medium cell alignment to unmodified-NOA81 topographical features, which allowed protein adsorption, differed significantly from cell alignment on RGD-modified features. These results demonstrate that the surface chemical composition significantly affects how HCECs respond to topographical cues. In summary, we have demonstrated modulation of the HCEC response to environmental cues through critical substrate and soluble parameters.