Preparation of water dispersible and biocompatible nanodiamond-poly(amino acid) composites through the ring-opening polymerization.

Nanodiamond (ND) is one of the most fascinating carbon materials that have been extensively investigated for biomedical applications owing to its small size, high specific surface areas, chemical inert and desirable biocompatibility. It has been reported that surface modification of ND with polymers could not only improve the dispersibility of final ND based composites but also endow them novel functions to fulfill the requirement for biomedical applications. Although some strategies have been developed previously, surface modification of ND with poly(amino acid)s has not been reported previously. In this work, poly(amino acid)s functionalized ND composites were fabricated through a ring-opening polymerization of α-amino acid N-carboxyanhydrides (NCAs), which was synthesized by conjugation of hydrophilic ethylene glycol with glutamic acid. The successful preparation of ND-GluEG composites was confirmed by a series of characterization techniques. The results suggest that the water dispersibility of final ND-GluEG composites is obviously improved. Moreover, ND-GluEG composites show low toxicity and are of great potential for biomedical applications.