Neodymium and manganese ions co-doped whitlockite for temperature monitoring, photothermal therapy, and bone tissue repair in osteosarcoma

Abstract

Osteosarcoma is one of the most dangerous forms of tumors, leading to death in >90% of patients. The surgical treatment of osteosarcoma results in significant bone defects and risks of tumor recurrence. Using neodymium (Nd) and manganese (Mn) ions co-doped with whitlockite nanoparticle (Nd10%Mn10%WH NPs) and sodium alginate (SA), we designed and synthesized an organic–inorganic composite hydrogel (Nd10%Mn10%WH-SA) that displayed the excellent fluorescence and photothermal properties. Furthermore, the maximum fluorescence emission intensity of Nd10%Mn10%WH-SA at 1062 nm was linear with temperature. The optimal temperature for the treatment of tumors was determined by considering the changes in fluorescence intensity that led to a reduction in tissue damage around the tumors. Nd10%Mn10%WH NPs demonstrated a significant function in promoting human bone marrow mesenchymal stem cells (hBMSCs) proliferation. Furthermore, Nd10%Mn10%WH-SA could almost kill tumors when the photothermal temperature was raised to 50 °C, with a minimal leftover scar after photothermal therapy (PTT). Nd10%Mn10%WH-SA had a better promotion effect on the growth of the new bone. These results suggested that Nd10%Mn10%WH-SA offers a new PTT method for the “integrated treatment and repair” of osteosarcoma.