32
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

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

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          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 (HA 300) and selenate (HA 300- 1.2SeO 4 ) or selenite (HA 300- 1.2SeO 3 ) 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 HA 300- 1.2SeO 4 and HA 300- 1.2SeO 3 , 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 HA 300- 1.2SeO 3 . 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.

          Related collections

          Most cited references33

          • Record: found
          • Abstract: found
          • Article: not found

          Chemical characterization of silicon-substituted hydroxyapatite.

          Bioceramic specimens have been prepared by incorporating a small amount of silicon (0.4 wt %) into the structure of hydroxyapatite [Ca10(PO4)6(OH)2, HA] via an aqueous precipitation reaction to produce a silicon-substituted hydroxyapatite (Si-HA). The results of chemical analysis confirmed the proposed substitution of the silicon (or silicate) ion for the phosphorus (or phosphate) ion in hydroxyapatite. The Si-HA was produced by first preparing a silicon-substituted apatite (Si-Ap) by a precipitation process. A single-phase Si-HA was obtained by heating/calcining the as-prepared Si-Ap to temperatures above 700 degrees C; no secondary phases, such as tricalcium phosphate (TCP), tetracalcium phosphate (TeCP), or calcium oxide (CaO), were observed by X-ray diffraction analysis. Although the X-ray diffraction patterns of Si-HA and stoichiometric HA appeared to be identical, refinement of the diffraction data revealed some small structural differences between the two materials. The silicon substitution in the HA lattice resulted in a small decrease in the a axis and an increase in the c axis of the unit cell. This substitution also caused a decrease in the number of hydroxyl (OH) groups in the unit cell, which was expected from the proposed substitution mechanism. The incorporation of silicon in the HA lattice resulted in an increase in the distortion of the PO4 tetrahedra, indicated by an increase in the distortion index. Analysis of the Si-HA by Fourier transform infrared (FTIR) spectroscopy indicated that although the amount of silicon incorporated into the HA lattice was small, silicon substitution appeared to affect the FTIR spectra of HA, in particular the P-O vibrational bands. The results demonstrate that phase-pure silicon-substituted hydroxyapatite may be prepared using a simple precipitation technique. Copyright 1999 John Wiley & Sons, Inc.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Bone tissue engineering with porous hydroxyapatite ceramics.

            The main principle of bone tissue engineering strategy is to use an osteoconductive porous scaffold in combination with osteoinductive molecules or osteogenic cells. The requirements for a scaffold in bone regeneration are: (1) biocompatibility, (2) osteoconductivity, (3) interconnected porous structure, (4) appropriate mechanical strength, and (5) biodegradability. We recently developed a fully interconnected porous hydroxyapatite (IP-CHA) by adopting the "form-gel" technique. IP-CHA has a three-dimensional structure with spherical pores of uniform size that are interconnected by window-like holes; the material also demonstrated adequate compression strength. In animal experiments, IP-CHA showed superior osteoconduction, with the majority of pores filled with newly formed bone. The interconnected porous structure facilitates bone tissue engineering by allowing the introduction of bone cells, osteotropic agents, or vasculature into the pores. In this article, we review the accumulated data on bone tissue engineering using the novel scaffold, focusing especially on new techniques in combination with bone morphogenetic protein (BMP) or mesenchymal stem cells.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Selenium deficiency-induced growth retardation is associated with an impaired bone metabolism and osteopenia.

              Although the importance of selenium for bone metabolism is unknown, some clinical conditions such as Kashin-Beck osteoarthropathy have been associated with selenium deficiency. Although selenium deficiency induces growth retardation in rats, it has not been established whether this growth inhibition is associated with changes in bone metabolism. We investigated the effect of selenium deficiency on bone metabolism in growing male rats fed a selenium-deficient diet for two generations (Se-). In Se- rats, erythrocyte glutathione peroxidase activity and plasma selenium concentration were strongly reduced compared with pair-fed selenium-adequate rats (Se+). Weight and tail length were reduced by 31% and 13% in the Se- rats, respectively (p < 0.001). The Se- diet was associated with a 68% reduction of pituitary growth hormone (GH; p = 0.01) and a 50% reduction of plasma insulin-like growth factor I (IGF-I; p < 0.001). Plasma calcium was lower and urinary calcium concentration was greater in Se- rats. This group had a 2-fold increase in parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] in plasma. Plasma osteocalcin and urinary deoxypyridoline were reduced by 25% and 57% in the Se- rats (p < 0.001). Selenium deficiency resulted in a 23% and 21% reduction in bone mineral density (BMD) of the femur and tibia (p < 0.001) and this effect persisted after adjustment for weight in a linear regression model. A 43% reduction in trabecular bone volume of the femoral metaphysis (p < 0.001) was found in Se- rats. This experimental study shows that growth retardation induced by selenium deficiency is associated with impaired bone metabolism and osteopenia in second-generation selenium-deficient rats.
                Bookmark

                Author and article information

                Contributors
                Role: Academic Editor
                Journal
                Int J Mol Sci
                Int J Mol Sci
                ijms
                International Journal of Molecular Sciences
                MDPI
                1422-0067
                19 May 2015
                May 2015
                : 16
                : 5
                : 11452-11464
                Affiliations
                Department of Inorganic and Analytical Chemistry, Faculty of Pharmacy with the Laboratory Medicine Division, Medical University of Warsaw, ul. Banacha 1, 02-097 Warsaw, Poland; E-Mails: marzena.kuras@ 123456wum.edu.pl (M.K.); eoledzka@ 123456wum.edu.pl (E.O.); marcin.sobczak@ 123456wp.pl (M.S.)
                Author notes
                [†]

                These authors contributed equally to this work.

                [* ]Author to whom correspondence should be addressed; E-Mail: joanna.kolmas@ 123456wum.edu.pl ; Tel.: +48-22-572-0755; Fax: +48-22-572-0784.
                Article
                ijms-16-11452
                10.3390/ijms160511452
                4463710
                25997001
                4cd9e169-8e70-4716-b621-2a4fc6163109
                © 2015 by the authors; licensee MDPI, Basel, Switzerland.

                This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license ( http://creativecommons.org/licenses/by/4.0/).

                History
                : 01 March 2015
                : 29 April 2015
                Categories
                Article

                Molecular biology
                biomaterials,calcium phosphates,hydroxyapatite,selenium oxyanions,solid-state nuclear magnetic resonance,powder diffractometry

                Comments

                Comment on this article