Sol-gel synthesis and characterization of magnetic TiO2 microspheres

Abstract

We tried to prepare magnetic TiO 2 microspheres as thermoseeds for hyperthermia of cancer by a solgel process from titanium tetraisopropoxide (TTIP) in a water-in-oil emulsion. The microspheres were prepared by the addition of diethanolamine (DEA) as stabilizer, methanol (CH 3 OH) as dispersant and colloidal £-Fe 2 O 3 nanoparticles as origin of magnetization. The £-Fe 2 O 3 nanoparticles were prepared by an oxidationprecipitation method in FeCl 2 NaNO 3 NaOH system. The diameter of microsphere was controlled by optimizing preparation conditions, i.e., molecular ratio of reactants and stirring speed. Mono-dispersed magnetic TiO 2 microspheres 1030 µm in diameter were sucessfully obtained by adding a certain amount of water phase with the molar ratio of TTIP/DEA/CH 3 OH/H 2 O = 1:1.7:7:22 into kerosene with surfactant (sorbitan monooleate/sorbitan monostearate = 3:1 in weight ratio) 16 wt % of the total amount of oil phase. They contained up to 26.7 wt % £-Fe 2 O 3 and their saturation magnetization and coercive force were 20.4 Am 2 /kg and 10 kA/m, respectively.

TiO2 microspheres containing magnetic nanoparticles for intra‐arterial hyperthermia

“…The biocompatibility of the microspheres used in this study should be improved in future, but it is noteworthy that this study revealed the fundamental conditions for obtaining MNP‐containing TiO 2 microspheres with heat‐generating ability ideal for hyperthermia, as well as a suitable particle size for arterial embolization, which were not described in our previous studies …”

“…MNPs modified with titanium dioxide (TiO 2 ) have also been proposed as photocatalytic thermoseeds in the induction of hyperthermia . Apart from the use of these MNPs or TiO 2 ‐modified MNPs in inducing hyperthermia, studies in our laboratory have focused on the induction of intra‐arterial hyperthermia using magnetic microspheres measuring 20–30 µm in diameter . The advantage of intra‐arterial hyperthermia using magnetic microspheres is that modification of particles with the often‐expensive tumor‐specific antibodies is not necessary, because the microspheres can be physically entrapped in the capillary vessels of tumors by arterial injection.…”

“…The advantage of intra‐arterial hyperthermia using magnetic microspheres is that modification of particles with the often‐expensive tumor‐specific antibodies is not necessary, because the microspheres can be physically entrapped in the capillary vessels of tumors by arterial injection. To date, ferrimagnetic magnetite microspheres, MNP‐containing silica (SiO 2 ) microspheres, iron‐containing SiO 2 microspheres, and MNP‐containing titanium dioxide (TiO 2 ) microspheres have been prepared, and their structures, magnetic properties, and in vitro heat‐generating ability have been investigated. However, the diameter of MNP‐containing TiO 2 microspheres was in the range of 10 − 20 µm or 7 − 15 µm, which is too small for intra‐arterial therapy.…”

Preparation and Characterization TiO2 Microspheres for the Liquid Chromatography Stationary Phase

“…TiO 2 has been extensively used in photocatalysis [1], lithium battery [2], sensor materials [3], dye degradation [4], cosmetics [5] and other technical fields [6]. In recent years titania materials for high performance liquid chromatography (HPLC) has attracted considerable attentionsattributed to the good chemical stability, mechanical strength, enough rigidity and amphoteric ion-exchange properties [7][8][9].…”

“…Titania has greater mechanical and pH stability (pH [1][2][3][4][5][6][7][8][9][10][11][12][13][14] that may compensate for the narrow pH range of silica and it is suitable for the separation of the alkaline substances especially the biological macromolecules [11]. Nowadays, the research about the TiO 2 used as the chromatographic packings instead of the silica column is less reported, not to mention the practical application.…”