Effects of Uptake of Hydroxyapatite Nanoparticles into Hepatoma Cells on Cell Adhesion and Proliferation

Hydroxyapatite nanoparticles (nano‐HAPs) were prepared by homogeneous precipitation, and size distribution and morphology of these nanoparticles were determined by laser particle analysis and transmission electron microscopy, respectively. Nano‐HAPs were uniformly distributed, with rod‐like shapes sizes ranging from 44.6 to 86.8 nm. Attached overnight, suspended, and proliferating Bel‐7402 cells were repeatedly incubated with nano‐HAPs. Inverted microscopy, transmission electron microscopy, and fluorescence microscopy were used to observe the cell adhesion and growth, the culture medium containing nano‐HAPs, the cell ultrastructure, and intracellular Ca 2+ labeled with a fluo‐3 calcium fluorescent probe. The results showed that nano‐HAPs inhibited proliferation of Bel‐7402 cells and, caused an obvious increase in the concentration of intracellular Ca 2+ , along with significant changes in the cell ultrastructure. Moreover, nano‐HAPs led suspended cells and proliferating cells after trypsinized that did not attach to the bottom of the culture bottle died. Nano‐HAPs continuously entered these cells. Attached, suspended, and proliferating cells endocytosed nano‐HAPs, and nanoparticle‐filled vesicles were in the cytoplasm. Therefore, hepatoma cellular uptake of nano‐HAPs through endocytosis was very active and occurred continuously. Nano‐HAPs affected proliferation and adhesion of hepatoma cells probably because uptake of nano‐HAPs blocked integrin‐mediated cell adhesion, which may have potential significance in inhibiting metastatic cancer cells to their target organ.