RGD Presenting Peptides in Amphiphilic and Anionic β-Sheet Hydrogels Improve Cell Adhesion

The interest in developing functional biomaterials, based on designed peptides is increasing in the recent years. Our lab has been studying amphiphilic and anionic β-sheet peptides one of which is Pro-Asp-(Phe-Asp)₅-Pro, denoted FD. This peptide was found to assemble into a hydrogel that induces the adsorption of calcium and phosphate ions en-route to forming the bone mineral hydroxyapatite. In this study, we were interested in evaluating the potential of using one of the most studied adhesion peptide sequences, Arg-Gly-Asp (RGD) to enhance osteoblasts interactions with the FD peptide hydrogels. The peptide FD-RGD composed of FD extended by RGD sequence could be mixed at any ratio with FD in solutions and in hydrogel phase. In solutions of the peptide mixtures in presence of calcium ions, the higher the FD content the more b-sheet structure was obtained. Similar trend was observed in hydrogels composed of mixtures of these peptides. Osteoblast cells cultured in hydrogel composed of 25% FD-RGD and 75% FD showed higher cell density compared cells in FD hydrogel. These results confirm that the mixed system of FD-RGD and FD improves cell-matrix interactions. Moreover, the evidence that RGD is active in the FD template supports the applicability of this dual peptide system design, for additional cell binding sequences.