TiO₂ microspheres containing magnetic nanoparticles for intra-arterial hyperthermia

Magnetic microspheres measuring 15-35 µm in diameter are believed to be useful for intra-arterial hyperthermia. In this study, we attempted to prepare titanium dioxide (TiO₂ ) microspheres containing magnetic nanoparticles (MNPs). MNP-containing TiO₂ microspheres with diameters of approximately 30 µm were successfully obtained by sol-gel reaction of titanium tetraisopropoxide in a water-in-oil emulsion with added cosurfactant of 1-butanol and subsequent heat treatment at 200°C. The microspheres showed ferrimagnetism owing to high content of MNPs in approximately 60 wt % and had a low-crystalline TiO₂ matrix. Furthermore, the agar phantom was heated to above 43°C after approximately 1 min under an alternating magnetic field of 100 kHz and 300 Oe and showed in vitro biocompatibility similar to that of MNP-free TiO₂ microspheres. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2308-2314, 2017.