Phytic acid-modified manganese dioxide nanoparticles oligomer for magnetic resonance imaging and targeting therapy of osteosarcoma.

Osteosarcoma is the most common malignant tumor in the skeletal system with high mortality. Phytic acid (PA) is a natural compound extracted from plant seeds, which shows certain antitumor activity and good bone targeting ability. To develop a novel theranostics for magnetic resonance imaging (MRI) and targeting therapy of osteosarcoma, we employed PA to modify manganese dioxide nanoparticles (MnO 2 @PA NPs) for osteosarcoma treatment. The MnO 2 NPs oligomer was formed by PA modification with uniformed size distribution and negative zeta potential. Fourier-transform infrared spectroscopy, X-ray diffraction, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis demonstrated that PA has been successfully modified on MnO 2 NPs, and the structure of MnO 2 @PA NPs is amorphous. In vitro experiments demonstrated that MnO 2 @PA NPs oligomer can be efficiently internalized by tumor cell, and the internalized NPs can react with H 2 O 2 under acid microenvironment to produce Mn 2+ and O 2 . In vivo experiments demonstrated that MnO 2 @PA NPs oligomer can passively accumulate in tumor tissue, and the accumulated NPs can produce Mn 2+ and O 2 for MRI and targeting therapy of osteosarcoma. In conclusion, we prepared a novel bone-targeting nano theranostics for MRI and therapy of osteosarcoma.