Effect of surface charge of TiO2 particles on hydroxyapatite formation in simulated body fluid

Masami Hashimoto, Satoshi Kitaoka, Hiroyasu Kanetaka

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


TiO2 particles formed by heat treatment in a nitrogen atmosphere with an extremely low oxygen partial pressure exhibited high hydroxyapatite (HAp)-forming ability in simulated body fluid (SBF). X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning transmission electron microscopy (STEM) combined with electron energy loss spectroscopy (EELS) indicated that the particles were rutile-type TiO2, which contains hardly any nitrogen. Electron spin resonance (ESR) spectra revealed the reduction of Ti4+ in TiO2 to Ti3+ and the simultaneous introduction of oxygen vacancies to maintain charge neutrality. The enhanced HAp-forming ability of the TiO2 particles was likely related to their negatively charged surface, induced by water adsorption on oxygen vacancies, which resulted in acidic point formation. In contrast, TiO2 particles formed by heat treatment in air showed low HAp-forming ability because their surfaces had almost zero charge.

Original languageEnglish
Pages (from-to)2409-2415
Number of pages7
JournalAdvanced Powder Technology
Issue number6
Publication statusPublished - 2016 Nov 1


  • Hydroxyapatite
  • Oxygen vacancy
  • Simulated body fluid
  • Surface charge
  • TiO particle

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Mechanics of Materials


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