Facile preparation of novel type polymethyl methacrylate/CoFe₂O₄/BNNS composite cements and their caloric performance in alternating magnetic fields

Abstract Magnetic hyperthermia generated by functionalized bone cement is a promising approach to treat postosteocarcinoma cancer regeneration. However, it is crucial to minimize the magnetic field intensity using localized high‐caloric‐generating nanoparticles to avoid the potential hazards of electromagnetic field exposure to living organisms. Herein, in situ hydrothermally synthesized CoFe 2 O 4 (CoFe) nanoparticles and boron nitride nanosheet (BNNS)–supported CoFe complexes (BNCoFe) are incorporated into polymethyl methacrylate (PMMA) cement to prepare a composite implant with high‐intensity magnetic–thermal performance and safety. The results show that the CoFe nanoparticles (size = ~70 nm) anchored on BNNS surfaces exhibit a maximum magnetic–thermal ablation temperature of ~42°C within 50 s under an alternating magnetic field of 400 KHz (field frequency) and 30 Oe (field intensity) in vitro. Furthermore, the incorporation of BNNSs into the PMMA matrix notably increases the thermal conductivity of PMMA from 0.07 to 0.25 W mK −1 and improves its mechanical properties (compressive strength increases from 74.0 ± 1.6 to 81.0 ± 1.0 MPa), which is attributed to the crystalline structure of BNNSs in the PMMA matrix. Inductively coupled plasma analysis shows a considerably reduced Co 2+ ion release from PMMA/BNCoFe, indicating its potential as a safe implantation material for hyperthermia treatment.