Novel degradable super-paramagnetic bone cement with self-controlled hyperthermia ability

Abstract

Hyperthermia treatment with magnetic bone cement can not only realize the highly targeted treatment of the deep-seated bone tumor but also repair the weakened bone tissue. However, the potential risk of overheating limits the use of this material. Herein, we report a novel super-paramagnetic injectable radiopaque bone cement (MSBC) that can control hyperthermia temperature by itself. The injectable MSBC was prepared by incorporating SiO2-modified nano Mn-Zn-Cu-Gd ferrites into an acidic calcium phosphate cement matrix. The SiO2 layer on the ferrites protects the oxides from reacting with the acid matrix vigorously to keep the good magnetic property. The acid matrix allows the ferrites to degrade gradually and almost one-tenth of MSBC degrades after soaking in phosphate buffer solution for 28 days. Moreover, MSBC can realize self-controlled hyperthermia around Curie temperature (65 ℃) in vitro under an alternating magnetic field. The X-ray transmission results show that the radiopacity of MSBC is significantly enhanced in comparison to the matrix. Furthermore, MSBC shows no cytotoxicity and can promote the mineralization ability of osteoblasts. Overall, this novel magnetic bone cement provides a new avenue for improving the thermal safety of magnetic hyperthermia treatment of bone tumors.