Multinuclear Solid-State NMR Studies of Ordered Mesoporous Bioactive Glasses

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• 作者：Ekaterina Leonova ; Isabel Izquierdo-Barba ; Daniel Arcos ; Adolfo Ló ; pez-Noriega ; Niklas Hedin ; Maria Vallet-Regí ; Mattias Ed&eacute ; n
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：April 10, 2008
• 年：2008
• 卷：112
• 期：14
• 页码：5552 - 5562
• 全文大小：336K
• 年卷期：v.112,no.14(April 10, 2008)
• ISSN：1932-7455

文摘

The local structures of highly ordered mesoporous bioactive CaO-SiO₂-P₂O₅ glasses were investigated forvariable Ca contents. ¹H NMR revealed a diversity of hydrogen-bonded and "isolated" surface silanols aswell as adsorbed water molecules. The structural roles of Si and P were explored using a combination of ²⁹Siand ³¹P magic-angle spinning (MAS) nuclear magnetic resonance (NMR) techniques; the proximities of Siand P to protons were studied through cross-polarization-based experiments, including ¹H-²⁹Si and ¹H-³¹Phetero-nuclear two-dimensional correlation spectroscopy. The results are consistent with SiO₂ being the mainpore-wall component, whereas P is present as a separate amorphous calcium orthophosphate phase, which isdispersed over the pore wall as nanometer-sized clusters. The excess Ca that is not consumed in the phosphatephase modifies the silica glass network where it associates at/near the mesoporous surface. This biphasicstructural model of the pore wall leads to the high accessibility of both Ca and P to body fluids, and itsrelation to the experimentally demonstrated high in vitro bioactivities of these materials is discussed.