A novel method to enhance magnetic property of bioactive glass-ceramics for hyperthermia

Abstract

In this study, a novel method was proposed to enhance the magnetic property of magnetic bioactive glass-ceramic (MBGC) using graphite-modified magnetite. The crystalline composition, chemical structure, in vitro bioactivity, magnetic property, heat generating ability, cytotoxicity and the hyperthermia treatment effectiveness of the synthesized material were investigated thoroughly. The results revealed that the addition of graphite could prevent the magnetite from being oxidized. The main phases of the as-prepared material were found to be Fe3O4, Ca2.87Fe0.13(SiO3)3 and Ca2SiO4 in the CaO-SiO2-MgO-CaF2-P2O5-Fe3O4 system. Moreover, the material was bioactive and hydroxyapatite was observed on the surface after soaking in simulated body fluid (SBF) for 10 d. Under a magnetic field of 1.6 × 106 A m−1, the saturation magnetization of MGBC was about 10.6 A m2 Kg−1, while that of the contrast sample was only 2.9 A m2 kg−1. When exposed to an alternating magnetic field (252 kHz, 1.9 × 103 A m−1) for about 20 s, a temperature rise of 20 °C could be observed on the sample surface. MTT assay results showed that the material had no cytotoxicity for VX2 cells. Moreover, the hyperthermia treatment experiments were carried out by exposing the block samples (Φ8 × 2 mm) and VX2 cells simultaneously to the alternating magnetic field for 20 min. Only about 30% cells survived after the treatment, and dead cells were observed around the material. Therefore, this novel material could have potential applications for clinical hyperthermia treatment.