骨肉瘤是骨骼系统中最常见的恶性肿瘤，死亡率较高。植物籽中提取的天然化合物植酸（PA）表现出一定的抗肿瘤活性和良好的骨靶向能力。为了开发一种新型的治疗骨肉瘤的磁共振成像（MRI）和靶向治疗的成像治疗联合系统，我们使用PA改性二氧化锰纳米颗粒（MnO2@PA NPs）来治疗骨肉瘤。通过PA改性形成了均匀尺寸分布和负电极势的MnO2 NPs寡聚体。傅里叶变换红外光谱、X射线衍射、能量色散谱、X射线光电子能谱和热重分析证明PA已成功修饰在MnO2 NPs上，并且MnO2@PA NPs的结构是非晶的。体外实验表明MnO2@PA NPs寡聚体能够有效地被肿瘤细胞内吞，内吞的NPs可以在酸性微环境下与H2O2反应产生Mn2+和O2。体内实验表明MnO2@PA NPs寡聚体可以被动积累在肿瘤组织中，积累的NPs可以产生Mn2+和O2，用于MRI和靶向治疗骨肉瘤。总之，我们制备了一种新型的靶向骨骼的纳米成像治疗联合系统，用于MRI和治疗骨肉瘤。

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 (MnO2@PA NPs) for osteosarcoma treatment. The MnO2 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 MnO2 NPs, and the structure of MnO2@PA NPs is amorphous. In vitro experiments demonstrated that MnO2@PA NPs oligomer can be efficiently internalized by tumor cell, and the internalized NPs can react with H2O2 under acid microenvironment to produce Mn2+ and O2. In vivo experiments demonstrated that MnO2@PA NPs oligomer can passively accumulate in tumor tissue, and the accumulated NPs can produce Mn2+ and O2 for MRI and targeting therapy of osteosarcoma. In conclusion, we prepared a novel bone-targeting nano theranostics for MRI and therapy of osteosarcoma.