Dissolution behavior of vaterite spherulite in solutions containing phosphate ions

Yuki Sugiura, Kazuo Onuma, Masahiro Nagao, Koichi Momma, Yuki Kimura, Atsushi Yamazaki

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Vaterite is a crystalline polymorph of calcium carbonate that exhibits low stability in comparison with the other crystalline polymorphs of calcium carbonate. It often assumes a spherical shape. The physical properties of vaterite are utilized in advanced biomaterials such as drug delivery systems (DDSs). The potential application of vaterite in DDSs demands a comprehensive understanding of its dissolution rate as a function of PO4concentration. Using in situ optical studies, we analyzed the dissolution behavior of vaterite in a simulated PO4-containing biogenic environment. The varying physicality (i.e., the pseudo-physiological conditions) of vaterite were investigated using high-resolution cryogenic transmission electron microscopy and small-angle X-ray scattering. In addition, we measured the PO4/Ca ratio in each part of vaterite spherulites using field-emission scanning electron microscopy in conjunction with energy-dispersive X-ray spectroscopy and inductively coupled plasma atomic emission spectrometry. We categorized the vaterite spherulites into three parts® the shell, mantle, and core parts® on the basis of their dissolution behavior and PO4response. The PO4response to the dissolution dynamics increases toward the outer part, although the adsorption rate decreases in the presence of PO4and PO4fluorescence materials. The composition of the shell part was nearly identical to that of ideal vaterite, whereas the inner part exhibited a high C/Ca ratio and a poorly crystalline phase referred to as vaterite-like material. The dissolution rate of each part was 0.231.58nm/ s (shell), 0.633.19nm/ s (mantle), and 1.385.71 nm/s (core). The vaterite and vaterite-like materials were further identified according to their composition and particle size distribution.

Original languageEnglish
Pages (from-to)679-687
Number of pages9
JournalJournal of the Ceramic Society of Japan
Volume122
Issue number1428
DOIs
Publication statusPublished - 2014 Aug 1

Keywords

  • Biomaterial
  • Calcium carbonate
  • Drug delivery systems
  • Phosphate
  • Spherulite
  • Vaterite

ASJC Scopus subject areas

  • Ceramics and Composites
  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry

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