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Proton Environments in Biomimetic Calcium Phosphates Formed from Mesoporous Bioactive CaO–SiO(2)–P(2)O(5) Glasses in Vitro: Insights from Solid-State NMR

[Image: see text] When exposed to body fluids, mesoporous bioactive glasses (MBGs) of the CaO–SiO(2)–P(2)O(5) system develop a bone-bonding surface layer that initially consists of amorphous calcium phosphate (ACP), which transforms into hydroxy-carbonate apatite (HCA) with a very similar compositio...

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Autores principales: Mathew, Renny, Turdean-Ionescu, Claudia, Yu, Yang, Stevensson, Baltzar, Izquierdo-Barba, Isabel, García, Ana, Arcos, Daniel, Vallet-Regí, María, Edén, Mattias
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2017
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5484558/
https://www.ncbi.nlm.nih.gov/pubmed/28663772
http://dx.doi.org/10.1021/acs.jpcc.7b03469
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author Mathew, Renny
Turdean-Ionescu, Claudia
Yu, Yang
Stevensson, Baltzar
Izquierdo-Barba, Isabel
García, Ana
Arcos, Daniel
Vallet-Regí, María
Edén, Mattias
author_facet Mathew, Renny
Turdean-Ionescu, Claudia
Yu, Yang
Stevensson, Baltzar
Izquierdo-Barba, Isabel
García, Ana
Arcos, Daniel
Vallet-Regí, María
Edén, Mattias
author_sort Mathew, Renny
collection PubMed
description [Image: see text] When exposed to body fluids, mesoporous bioactive glasses (MBGs) of the CaO–SiO(2)–P(2)O(5) system develop a bone-bonding surface layer that initially consists of amorphous calcium phosphate (ACP), which transforms into hydroxy-carbonate apatite (HCA) with a very similar composition as bone/dentin mineral. Information from various (1)H-based solid-state nuclear magnetic resonance (NMR) experiments was combined to elucidate the evolution of the proton speciations both at the MBG surface and within each ACP/HCA constituent of the biomimetic phosphate layer formed when each of three MBGs with distinct Ca, Si, and P contents was immersed in a simulated body fluid (SBF) for variable periods between 15 min and 30 days. Directly excited magic-angle-spinning (MAS) (1)H NMR spectra mainly reflect the MBG component, whose surface is rich in water and silanol (SiOH) moieties. Double-quantum–single-quantum correlation (1)H NMR experimentation at fast MAS revealed their interatomic proximities. The comparatively minor H species of each ACP and HCA component were probed selectively by heteronuclear (1)H–(31)P NMR experimentation. The initially prevailing ACP phase comprises H(2)O and “nonapatitic” HPO(4)(2–)/PO(4)(3–) groups, whereas for prolonged MBG soaking over days, a well-progressed ACP → HCA transformation was evidenced by a dominating O(1)H resonance from HCA. We show that (1)H-detected (1)H → (31)P cross-polarization NMR is markedly more sensitive than utilizing powder X-ray diffraction or (31)P NMR for detecting the onset of HCA formation, notably so for P-bearing (M)BGs. In relation to the long-standing controversy as to whether bone mineral comprises ACP and/or forms via an ACP precursor, we discuss a recently accepted structural core–shell picture of both synthetic and biological HCA, highlighting the close relationship between the disordered surface layer and ACP.
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spelling pubmed-54845582017-06-27 Proton Environments in Biomimetic Calcium Phosphates Formed from Mesoporous Bioactive CaO–SiO(2)–P(2)O(5) Glasses in Vitro: Insights from Solid-State NMR Mathew, Renny Turdean-Ionescu, Claudia Yu, Yang Stevensson, Baltzar Izquierdo-Barba, Isabel García, Ana Arcos, Daniel Vallet-Regí, María Edén, Mattias J Phys Chem C Nanomater Interfaces [Image: see text] When exposed to body fluids, mesoporous bioactive glasses (MBGs) of the CaO–SiO(2)–P(2)O(5) system develop a bone-bonding surface layer that initially consists of amorphous calcium phosphate (ACP), which transforms into hydroxy-carbonate apatite (HCA) with a very similar composition as bone/dentin mineral. Information from various (1)H-based solid-state nuclear magnetic resonance (NMR) experiments was combined to elucidate the evolution of the proton speciations both at the MBG surface and within each ACP/HCA constituent of the biomimetic phosphate layer formed when each of three MBGs with distinct Ca, Si, and P contents was immersed in a simulated body fluid (SBF) for variable periods between 15 min and 30 days. Directly excited magic-angle-spinning (MAS) (1)H NMR spectra mainly reflect the MBG component, whose surface is rich in water and silanol (SiOH) moieties. Double-quantum–single-quantum correlation (1)H NMR experimentation at fast MAS revealed their interatomic proximities. The comparatively minor H species of each ACP and HCA component were probed selectively by heteronuclear (1)H–(31)P NMR experimentation. The initially prevailing ACP phase comprises H(2)O and “nonapatitic” HPO(4)(2–)/PO(4)(3–) groups, whereas for prolonged MBG soaking over days, a well-progressed ACP → HCA transformation was evidenced by a dominating O(1)H resonance from HCA. We show that (1)H-detected (1)H → (31)P cross-polarization NMR is markedly more sensitive than utilizing powder X-ray diffraction or (31)P NMR for detecting the onset of HCA formation, notably so for P-bearing (M)BGs. In relation to the long-standing controversy as to whether bone mineral comprises ACP and/or forms via an ACP precursor, we discuss a recently accepted structural core–shell picture of both synthetic and biological HCA, highlighting the close relationship between the disordered surface layer and ACP. American Chemical Society 2017-05-23 2017-06-22 /pmc/articles/PMC5484558/ /pubmed/28663772 http://dx.doi.org/10.1021/acs.jpcc.7b03469 Text en Copyright © 2017 American Chemical Society This is an open access article published under an ACS AuthorChoice License (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html) , which permits copying and redistribution of the article or any adaptations for non-commercial purposes.
spellingShingle Mathew, Renny
Turdean-Ionescu, Claudia
Yu, Yang
Stevensson, Baltzar
Izquierdo-Barba, Isabel
García, Ana
Arcos, Daniel
Vallet-Regí, María
Edén, Mattias
Proton Environments in Biomimetic Calcium Phosphates Formed from Mesoporous Bioactive CaO–SiO(2)–P(2)O(5) Glasses in Vitro: Insights from Solid-State NMR
title Proton Environments in Biomimetic Calcium Phosphates Formed from Mesoporous Bioactive CaO–SiO(2)–P(2)O(5) Glasses in Vitro: Insights from Solid-State NMR
title_full Proton Environments in Biomimetic Calcium Phosphates Formed from Mesoporous Bioactive CaO–SiO(2)–P(2)O(5) Glasses in Vitro: Insights from Solid-State NMR
title_fullStr Proton Environments in Biomimetic Calcium Phosphates Formed from Mesoporous Bioactive CaO–SiO(2)–P(2)O(5) Glasses in Vitro: Insights from Solid-State NMR
title_full_unstemmed Proton Environments in Biomimetic Calcium Phosphates Formed from Mesoporous Bioactive CaO–SiO(2)–P(2)O(5) Glasses in Vitro: Insights from Solid-State NMR
title_short Proton Environments in Biomimetic Calcium Phosphates Formed from Mesoporous Bioactive CaO–SiO(2)–P(2)O(5) Glasses in Vitro: Insights from Solid-State NMR
title_sort proton environments in biomimetic calcium phosphates formed from mesoporous bioactive cao–sio(2)–p(2)o(5) glasses in vitro: insights from solid-state nmr
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5484558/
https://www.ncbi.nlm.nih.gov/pubmed/28663772
http://dx.doi.org/10.1021/acs.jpcc.7b03469
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