Tracking of cellular uptake of hydrophilic CdSe/ZnS quantum dots/hydroxyapatite composites nanoparticles in MC3T3-E1 osteoblast cells.

We report the fluorescent labeling of osteoblast cells using the biocompatible hydroxyapatite (HA) grown with nucleating seed of hydrophilic CdSe/ZnS quantum dots (QDs) allowing the real-time observation of cell under confocal microscope. We found that the MC3T3-E1 osteoblast cells can engulf HA with surface-tailored QDs showing fluorescent spots in the cytoplasm, while HA and QDs nanoparticles were not engulfed. It is interesting to see that the fluorescence was only displayed in the cytoplasm of MC3T3-E1 osteoblast cells. It can be envisioned that the nano-sized hydroxyapatite bearing fluorescent QD can only be internalized in the cytoplasm. Therefore, it is worth utilizing these composite particles to observe cellular physiology with minimal toxicity to the osteoblast cells.