Strontium incorporated hydroxyapatite/hydrothermally reduced graphene oxide nanocomposite as a cytocompatible material

Hydroxyapatite (HA)/reduced graphene oxide (rGO) composites with different mol% of strontium and 1 wt% of GO were fabricated through a green hydrothermal reduction method and this combination has been reported for the first time. All the synthesized composites had strontium incorporated onto the crystal structure of HA as can be substantiated from XRD and FTIR. This paper also discusses a possible role of surface and pore characteristics on the in vitro cytocompatibility and the contribution of graphene oxide in directing the nucleation points resulting in dispersed strontium incorporated hydroxyapatite (SHA) based on P-31 NMR and TEM studies. In addition, a reasonable speculation also has been made to correlate the cytocompatibility with the selective occupancy of strontium ions in the apatite lattice. The in vitro cytocompatibility of SHA/rGO composites (SHAG) has been evaluated using cell proliferation tests with MG-63 cells, under a wider range of concentrations (1000–7.8 µg/ml) and by varying Sr/(Ca+Sr) molar ratio. SHAG with strontium substitution of 10 mol% exhibited the maximum viability among the samples tested. These results suggest that the SHAG composites will be a promising material for biomedical application.