Synthesis and hyperthermia property of hydroxyapatite–ferrite hybrid particles by ultrasonic spray pyrolysis

Abstract

Biocompatible hybrid particles composed of hydroxyapatite (Ca10(PO4)6(OH)2, HAp) and ferrite (γ-Fe2O3 and Fe3O4) were synthesized using a two-step procedure. First, the ferrite particles were synthesized by co-precipitation. Second, the suspension, which was composed of ferrite particles by a co-precipitation method, Ca(NO3)2, and H3PO4 aqueous solution with surfactant, was nebulized into mist ultrasonically. Then the mist was pyrolyzed at 1000°C to synthesize HAp–ferrite hybrid particles. The molar ratio of Fe ion and HAp was (Fe2+ and Fe3+)/HAp=6. The synthesized hybrid particle was round and dimpled, and the average diameter of a secondary particle was 740nm. The cross section of the synthesized hybrid particles revealed two phases: HAp and ferrite. The ferrite was coated with HAp. The synthesized hybrid particles show a saturation magnetization of 11.8emu/g. The net saturation magnetization of the ferrite component was calculated as 32.5emu/g. The temperature increase in the AC-magnetic field (370kHz, 1.77kA/m) was 9°C with 3.4g (the ferrite component was 1.0g). These results show that synthesized hybrid particles are biocompatible and might be useful for magnetic transport and hyperthermia studies.