Nanocomposite Hydrogels from Nanodiamonds and a Self-Assembling Tripeptide

We report the successful assembly of a tripeptide in the presence of nanodiamonds (NDs) into nanocomposite hydrogels. While the presence of NDs does not hinder peptide self-assembly and gelation kinetics are not affected, NDs improve the viscoelastic properties and significantly increase the elastic moduli of the peptide hydrogels. Increased resistance of the gels against applied stress can also be attained depending on the amount of NDs loaded in the nanocomposite. Raman micro-spectroscopy and TEM confirmed the presence of NDs on the surface, and not in the interior, of peptide nanofibers. Peptide-ND non-covalent interactions are also probed by Raman and Fourier-transformed infrared spectroscopies. Overall, this work enables the embedding of NDs into nanocomposite hydrogels formed through the self-assembly of a simple tripeptide at physiological pH, and it provides key insights to open the way for their future applications in biomaterials, for instance exploiting their luminescence and near-infrared responsiveness.