A Novel, Targeted, Injectable Magnetic Composite for Self‐Regulating Mild Hyperthermia Treatment of Bone Tumors with Improved Safety

Abstract Magnetic hyperthermia (MH) mediated by biomaterials is a novel and promising method for treating deep‐seated bone tumors; however, it is crucial to control the temperature to ensure efficacy and safety. In this study, a novel injectable magnetic composite cement (BBCM@HA) with self‐regulating hyperthermic effects by loading hyaluronic acid (HA)‐modified lanthanum strontium calcium manganese oxide on a matrix composed of calcium phosphate, calcium sulfate, and bioactive glass is developed. The cement has good injectability, can self‐harden, resists washout, and is radiopaque. Cell experiments reveal that BBCM@HA can increase the proliferation, migration, mineralization, and alkaline phosphatase expression in MC3T3 cells. Notably, the cement with a Curie temperature of ≈50 °C can achieve stable, self‐regulating mild MH in vivo under a biosafe alternating magnetic field (AMF), thus showing enhanced safety. Upon AMF application, the material kills MG63 cells in vitro and significantly suppresses subcutaneous tumor growth in mice. In addition, BBCM@HA repairs the bone defects formed by VX2 tumors in rabbits and inhibits bone tumor recurrence. Thus, BBCM@HA can treat bone tumors via self‐regulated mild hyperthermia.