Surface reactivity of octacalcium phosphate-derived fluoride-containing apatite in the presence of polyols and fluoride

• Published in: Journal of biomedical materials research. Part B, Applied biomaterials Applied biomaterials, 2018-08, Vol.106 (6), p.2235-2244
• Main Authors: Tsutsui, Sei, Anada, Takahisa, Shiwaku, Yukari, Tsuchiya, Kaori, Yamazaki, Hajime, Suzuki, Osamu
• Format: Article
• Language: English
• Subjects: Adsorption; Apatite; Biomedical materials; Calcium phosphates; Chemical synthesis; Crystals; Dissolution; Fluorapatite; Fluorides; Glycerol; Human serum albumin; Hydroxyapatite; Lactic acid; Materials research; Materials science; Mineralization; Octacalcium phosphate; Polyols; Serum albumin; Sorbitol; Surface chemistry; Surface reactions; X-ray diffraction; Xylitol
• ISSN: 1552-4973; 1552-4981
• DOI: 10.1002/jbm.b.34026

The present study was designed to characterize co-precipitated fluoridated apatitic materials from octacalcium phosphate (OCP) precursor and to investigate their surface reactions with polyols including glycerol in the presence of fluoride ions. Laboratory-synthesized fluoridated apatite crystals (LS-FA) were obtained in a solution containing fluoride (F) from 25 to 500 ppm. LS-FAs and commercially available fluoroapatite (FA) and hydroxyapatite (HA) were characterized by physical techniques, such as X-ray diffraction. LS-FA obtained in the presence of 100 ppmF (100 ppm-LS-FA) had an apatitic structure, but its solubility was close to HA in a culture medium (α-MEM) despite the fact it contains over 3 wt % of F. 100 ppm-LS-FA, FA, and HA were then subjected to the human serum albumin (HSA) adsorption test at pH 7.4 (in a 150 mM Tris-HCl buffer) and the dissolution and re-mineralization experiments in the presence of xylitol, D-sorbitol, or glycerol, and F under acidic and neutral conditions. Adsorption affinity of HSA was estimated as highest for FA and lowest for LS-FA. LS-FA, FA, and HA were immersed in a lactic acid solution with the polyols and/or F ion-containing solution up to 200 ppm to analyze the dissolution behavior. LS-FA had the highest dissolution tendency in the conditions examined. Glycerol enhanced the dissolution of phosphate from apatite crystals in particular from LS-FA. The results suggest that the apatite crystals, obtained through the hydrolysis of OCP in the presence of F, provide a more reactive surface than FA or HA under physiological environments. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2235-2244, 2018.