Spark Plasma Sintered HA‐Fe3O4‐Based Multifunctional Magnetic Biocomposites

Although HA is highly biocompatible, one of the major disadvantages of HA include the lack of antibacterial property. In an earlier study, we demonstrated the potential role of magnetic field stimulation on bactericidal property in vitro. Following this, it was hypothesized that antibacterial property can be realized if bacteria are grown on magnetic biocomposites in vitro. In addressing this issue, this study demonstrates the development of HA‐Fe₃O₄‐based magnetic substrate with multifunctional properties. For this purpose, HA‐xFe₃O₄ (x: 10, 20 and 40 wt%) powder compositions were sintered using uniquely designed spark plasma sintering conditions (three stage sintering with final holding temperature of 1050°C for 5 min). A saturation magnetization of 24 emu/g is measured with HA‐40%Fe₃O₄. Importantly, all the HA‐Fe₃O₄ composites demonstrated bactericidal property by rupturing the membrane of Escherichia coli bacteria, while supporting cell growth of metabolically active human fetal osteoblast cells over 8 d culture. A systematic decrease in bacterial viability with Fe₃O₄ addition is consistent with a commensurate increase in reactive oxygen species (ROS).