Biocompatible Fluorescent Hydroxyapatite: Synthesis and Live Cell Imaging Applications

Various fluorescent nanoparticles have been applied in imaging of tissues or intracellular structures. Searching for biocompatible nanoparticles that can be observed under visible light is of fundamental importance for the applications in living cells. In this study, a simple, template-based route for the synthesis of fluorescent hydroxyapatite (HA) nanoparticles has been developed. Well-dispersed HA nanoparticles prepared by using SiO2 as templates (THA) were surface-functionalized with fluorescein isothiocyanate (FITC), resulting in bright and stable fluorescent particles (THA-FITC). These fluorescent nanoparticles were demonstrated to be internalized into Hela cells and have no apparent cytotoxic effects on fibroblast cells, which confirmed the biocompatibility and cell labeling capability of the nanoparticles. Due to the large surface areas, porous nature, and visible light excited luminescence characters, THA-FITC nanoparticles will have applications in fields such as cell labeling, whole animal imaging and therapy, and drug delivery and release.