Corneal epithelial wound healing on bilayer composite hydrogels.

We demonstrate that a bilayer composite hydrogel composed of corneal stroma crosslinked to poly(ethylene oxide) provides a substrate suitable for wound healing behavior of corneal epithelial cells and for formation and maintenance of a stable multilayered epithelium. Potential diffusion-limitation of nutrients or regulatory molecules across the hydrogel was investigated experimentally with a new in vitro ocular assay, using epithelial cell migration as an index of molecular diffusion limitations. Corneal epithelial cells explanted on the composite hydrogel in vitro exhibited morphology similar to those in vivo, and migrated effectively over the stromal surface. Importantly, our system yielded multilayered epithelium like that found in normal corneal tissue under conditions that closely simulate the in vivo physiologic arrangement. In addition, our results indicate that molecules of substantially greater molecular weight than glucose appear to control the cell migration rate. Thus, engineering design of this composite hydrogel system may allow it to be useful in corneal wound healing applications.