Incorporation of cell-adhesion peptides into collagen scaffolds promotes corneal epithelial stratification

The objective of this study was to examine the effects of cell-adhesion peptides incorporated into collagen scaffolds on corneal epithelial cell stratification. Peptides (YIGSR, YIGSRIKVAV, IKVAVYIGSR and negative control YISGR) were first chemically attached to dendrimers. The peptide-modified dendrimers were then used as collagen cross-linkers. This permitted the incorporation of the peptides into the bulk structure of the collagen gels. The amount of peptide incorporated into the collagen gels was determined by I-125 radiolabelling to be between 0.064 and 6.4 mu g/mg collagen for YIGSR, and between 0.1187 to 11.87 mu g/mg collagen for YIGSRIKVAV and IKVAVYIGSR. Corneal epithelial cell monolayers were grown on the surface of the collagen scaffolds and then exposed to conditions that promoted stratification as a stratified epithelial layer is desired in a tissue-engineered cornea. It was found that all of the incorporated peptides promoted stratification of the cells with the exception of the negative control YISGR. A synergistic effect of the combined sequences from laminin was observed, with the orientation of the peptide sequences having a great impact on the ability of the materials to promote cell stratification.