Modification of native collagen with cell-adhesive peptide to promote RPE cell attachment on Bruch's membrane.

Current efforts to reverse loss of visual function due to Age-related Macular Degeneration point to the restoration of the Retinal Pigment Epithelial (RPE) layer. Restoration of the RPE layer involves replacing lost RPE cells as well as addressing the degeneration of the underlying Bruch's membrane (BM). To advance the potential of using donor BM, we present a strategy to achieve specific and controllable modification of the inner collagenous layer (ICL) of the Bruch's membrane. In particular, interaction between a collagen binding peptide (CBP) sequence with exposed collagen fibers on the ICL surface is utilized to anchor bioactive molecules. Here, a cell-adhesion sequence is added to the collagen binding sequence to promote attachment and survival of ARPE-19. First, the binding specificity of the CBP sequence is verified with a fluorescent binding assay. Subsequently, the effect of modification using the peptide is studied qualitatively using confocal fluorescent imaging and quantitatively through a cell proliferation assay. Results of these experiments indicate that the peptide sequence binds specifically to collagen fibers. Additionally, modification using the peptide enhanced cell adhesion, allowing large uniform cell networks to be formed on the surface. Furthermore, modification with the peptide also delayed the onset of apoptosis on adherent cells.