Collagen functionalized graphene sheets decorated with in situ synthesized nano hydroxyapatite electrospun into fibers

Abstract

We report the in situ synthesis of hydroxyapatite nanoparticles on 1–3 layers of colloidal collagen-graphene composites. Varying calcium and phosphate: graphene ratio two different composites were synthesized. Crystallite size, particle size and degree of crystallinity of hydroxyapatite nanoparticles changes with a change in graphene concentration. Transmission electron microscopy shows that these graphene composites change shape from spherical to elongated needle-like structures because of the varying nitrogen content in collagen-graphene. Fourier-transform Infrared Spectroscopy peaks suggests an interaction between calcium and the colloidal composites. X-ray Photo Electron spectroscopy data shows the interaction between graphene, collagen and hydroxyapatite through pyridinic N-oxide moiety. High-resolution lattice images confirm the co-existence of both graphene and hydroxyapatite. Anti-bacterial tests of the colloidal composites with two different bacteria S. Marcences and E. Coli show improved anti- bacterial property with increased graphene concentration. The colloidal composites were further electrospun into fibers, and their electrochemical stability in simulated body fluids estimated. The electrochemical test data show that the fiber made of composites would be extremely useful for biomedical applications such as internal bandages and burns.