Mesoporous fluoridated hydroxyapatite nanorods as a multifunctional platform for potential cancer-induced bone defect repair

Abstract

Objective For cancer-induced bone defects, cancer therapy is as important as tissue repair. Therefore, multifunctional materials with both anticancer and regenerative properties are urgently needed. Methods Here, we prepared mesoporous FAp (MFAp) nanorods with uniform morphology by a one-pot method, with a diameter of about 15 nm and a length of about 100 nm. MFAp nanorods possess high cytocompatibility even at a 1000 μg/mL high concentration. The fluorescence visualization based on terbium (Tb) doping confirmed that MFAp nanorods could be endocytosed efficiently. MFAp nanorods adsorbed doxorubicin (DOX) effectively due to the high specific surface area, forming DOX-MFAp hybrids. For bone repair, materials often act synergistically with functional cells or their secretions. We therefore studied the combined effects of MFAp nanorods and umbilical vein endothelial cells (UVECs), which secrete BMP-2. MFAp nanorods were internalized by bone marrow mesenchymal stem cells (BMMSCs), which were subsequently co-cultured with UVECs to form a multicellular structure. Results There was a pH-responsive release of DOX from DOX-MFAp nanorods, which could help DOX to be delivered into the cytoplasm and then transported into the nuclei. Consequently, DOX-MFAp nanorods have elevated lethality to cancer cells compared with free DOX at the equivalent concentration. Results showed that MFAp nanorods promoted osteogenic differentiation of BMMSCs with UVECs' assistance, even without added growth factors, highlighting their clinical potential. Conclusion In summary, MFAp nanorods could function as a promising platform for cancer-induced bone defect repair by integrating efficient drug delivery with enhanced osteogenesis.