A “biomimetic bone-magnet” with suitable mechanical properties concurrently performs accurate target collection of nanoparticles for magnetothermally driven osteosarcoma thermo-chemotherapy

Abstract

Osteolytic lesions of bone tumors lead to stress-induced loss of load-bearing bones, making it difficult to treat tumors and repair bone tissue structures. Magnetic hyperthermia has become an effective minimally invasive treatment for malignant bone tumors without depth limitations. However, the effectiveness of magnetic heat therapy alone is not satisfactory, and if combined with chemotherapy, it can lead to significant systemic side effects. It is important to efficiently target chemotherapy substances to the correct area for combined therapy. We have developed a biomimetic bone magnet (BBM) that uses polymethyl methacrylate (PMMA) bone cement-loaded permanent magnet materials with good support performance to create an intrinsic tumor magnetic field. This magnetic field has magnetothermal properties and collects drug-loaded magnetic phase change nanoparticles (mCNPs) circulating in the blood for magnetothermally triggered chemotherapy. Moreover, PMMA has good mechanical properties, providing potential stress support for bone reconstruction after bone tumor treatment. Importantly, both in vivo and in vitro experimental results demonstrated the effectiveness of magnetic hyperthermia through minimally invasive injection of BBM phase transition. This new method achieves magnetic targeting by manufacturing tumor biomagnets to generate strong magnetic fields within the tumor, which opens up new avenues for treatment strategies for malignant bone tumors.