RGD-presenting peptides in amphiphilic and anionic β-sheet hydrogels for improved interactions with cells.

The interest in developing functional biomaterials based on designed peptides has been increasing in recent years. The amphiphilic and anionic β-sheet peptide Pro-Asp-(Phe-Asp)-Pro, denoted FD, was previously shown to assemble into a hydrogel that induces adsorption of calcium and phosphate ions and formation of the bone mineral hydroxyapatite. In this study the integrin binding peptide, Arg-Gly-Asp (RGD), was incorporated into the hydrogel to assess its influence on an osteoblast culture. In solutions and in hydrogels FD fibrils dominated the assembly structures for up to 25 mol% FD-RGD incorporation. The cellular density of osteoblasts cultured in hydrogels composed of 25 mol% FD-RGD in FD was higher than that of only FD hydrogel cultures. These results demonstrate that RGD and possibly other cell binding motifs can be combined into amphiphilic and anionic β-sheet hydrogels, using the design principles of FD and FD-RGD systems, to enhance interactions with cells.