title: Enzymatic preparation of hollow magnetite microspheres for hyperthermic treatment of cancer.
abstract: Ferrimagnetic materials can be expected to be useful as thermal seeds for hyperthermic treatment of cancer, especially where the cancer is located in deep parts of body, as they can generate heat by magnetic hysteretic loss when they are placed in an alternating magnetic field. In this study, hollow magnetite (Fe(3)O(4)) particles were prepared using an enzymatic reaction of urease. A hollow particle was obtained by using a Pasteur pipette. The particle was 500 microm in size and was composed of Fe(3)O(4). Its saturation magnetization and coercive force were 57 emuxg(-1) and 183 Oe, respectively. Its heat generation under an alternating magnetic field of 300 Oe at 100 kHz was estimated to be 45 Wxg(-1). Microspheres 30 microm in diameter were also successfully obtained by using a spray gun.
authors.affiliation: Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan. kawashita@kuee.kyoto-u.ac.jp
authors.forename: Masakazu
authors.initials: M
authors.lastname: Kawashita
authors.forename: Kazuo
authors.initials: K
authors.lastname: Sadaoka
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kokubo
authors.forename: Takashi
authors.initials: T
authors.lastname: Saito
authors.forename: Mikio
authors.initials: M
authors.lastname: Takano
authors.forename: Norio
authors.initials: N
authors.lastname: Araki
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hiraoka
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004574:Electromagnetic Fields; D052203:Ferrosoferric Oxide; D006358:Hot Temperature; D006801:Humans; D006979:Hyperthermia, Induced / Q000379:methods*; D007501:Iron / Q000737:chemistry* / Q000528:radiation effects*; D008280:Magnetics / Q000627:therapeutic use*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D009369:Neoplasms / Q000628:therapy*; D010087:Oxides / Q000737:chemistry* / Q000528:radiation effects*; D010316:Particle Size; D011829:Radiation Dosage
chemical_list: D001672:Biocompatible Materials; D010087:Oxides; D007501:Iron; D052203:Ferrosoferric Oxide