A Solid-State NMR Study of Selenium Substitution into Nanocrystalline Hydroxyapatite

International Journal of Molecular Sciences

Joanna Kolmas¹  Marzena Kuras¹  Ewa Oledzka¹  Marcin Sobczak¹ 

关键词: biomaterials;    calcium phosphates;    hydroxyapatite;    selenium oxyanions;    solid-state nuclear magnetic resonance;    powder diffractometry;   

DOI  :  10.3390/ijms160511452

来源: mdpi

【 摘 要 】

The substitution of selenium oxyanions in the hydroxyapatite structure was examined using multinuclear solid-state resonance spectroscopy (ssNMR). The study was supported by powder X-ray diffractometry (PXRD) and wavelength dispersion X-ray fluorescence (WD-XRF). Samples of pure hydroxyapatite (HA₃₀₀) and selenate (HA₃₀₀-1.2SeO₄) or selenite (HA₃₀₀-1.2SeO₃) substituted hydroxyapatites were synthesized using the standard wet method and heated at 300 °C to remove loosely bonded water. PXRD data showed that all samples are single-phase, nanocrystalline hydroxyapatite. The incorporation of selenite and selenate ions affected the lattice constants. In selenium-containing samples the concentration of Se was very similar and amounted to 9.55% and 9.64%, for HA₃₀₀-1.2SeO₄ and HA₃₀₀-1.2SeO₃, respectively. PXRD and ssNMR data showed that the selenite doping significantly decreases the crystallite size and crystallinity degree. ³¹P and ¹H NMR experiments demonstrated the developed surface hydrated layer in all samples, especially in HA₃₀₀-1.2SeO₃. ¹H NMR studies showed the dehydroxylation of HA during the selenium oxyanions substitution and the existence of hydrogen bonding in structural hydroxyl group channels. ¹H→⁷⁷Se cross polarization NMR experiments indicated that selenites and selenates are located in the crystal lattice and on the crystal surface.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.