Treatment for osteoclast in vitro. (A) CCK-8 assay for BMMs treated with different concentrations of the MSN and MCD nanoparticles with or without irradiation after 24 h or 72 h culture. The unit of concentration is μg/L. (B) Live/Dead fluorescence images of BMMs. Scale bar, 200 μm. (C) Statistical analyses of Live/Dead experiments. (D) Expression of osteoclast marker genes, including c-Fos, CTSK, NFATc1, and DC-STAMP. (E) Osteoclasts stained for TRAP. Scale bar, 500 μm. (F) TRAP staining, number, and size of the TRAP+ osteoclasts with > 5 nuclei were quantified. (G–H) F-actin staining for osteoclast and F-actin analysis. Scale bar, 200 μm. (I–J) Bone resorption experiment and analysis. Scale bar, 200 μm. (K) WB analysis of relative protein expressions in different groups. (L) Schematic diagram of co-culture of BMMs with 143B and U2OS. *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001.