Multifunctional biodegradable terbium-doped calcium phosphate nanoparticles: facile preparation, pH-sensitive drug release and in vitro bioimaging

A facile room-temperature solution method for the preparation of biodegradable terbium (Tb)-doped calcium phosphate (CaP) nanoparticles is reported. The morphology, chemical composition, photoluminescence (PL), drug loading/release, cell viability and in vitro bioimaging of as-prepared Tb-CaP nanoparticles are investigated. The Tb-CaP nanoparticles consist of an amorphous phase. The PL of Tb-CaP nanoparticles with a strong emission at 544 nm is realized by doping Tb3+ ions. The Tb-CaP nanoparticles exhibit a good docetaxel (Dtxl) drug loading capacity and pH-responsive drug release. The mechanism of pH-responsive drug release can be explained by the gradual dissolution of CaP nanoparticles in a lower pH solution. The Tb-CaP nanoparticles have a high biocompatibility. The Dtxl-loaded Tb-CaP nanoparticles exhibit an inhibition for the cell viability of human Glioma Cell Line (U87) in vitro. Furthermore, there is a distinguished imaging signal when the U87 cells are co-cultured with the Tb-CaP nanoparticles in vitro. It is significant to develop Tb-CaP nanoparticles which are promising for applications in drug delivery, tissue engineering, bioimaging, etc.