Multinuclear Solid-State NMR Studies of Ordered Mesoporous Bioactive Glasses
2008 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, Vol. 112, no 14, 5552-5562 p.Article in journal (Refereed) Published
The local structures of highly ordered mesoporous bioactive CaO-SiO2-P2O5 glasses were investigated for variable Ca contents. 1H NMR revealed a diversity of hydrogen-bonded and "isolated" surface silanols as well as adsorbed water molecules. The structural roles of Si and P were explored using a combination of 29Si and 31P magic-angle spinning (MAS) nuclear magnetic resonance (NMR) techniques; the proximities of Si and P to protons were studied through cross-polarization-based experiments, including 1H-29Si and 1H-31P hetero-nuclear two-dimensional correlation spectroscopy. The results are consistent with SiO2 being the main pore-wall component, whereas P is present as a separate amorphous calcium orthophosphate phase, which is dispersed over the pore wall as nanometer-sized clusters. The excess Ca that is not consumed in the phosphate phase modifies the silica glass network where it associates at/near the mesoporous surface. This biphasic structural model of the pore wall leads to the high accessibility of both Ca and P to body fluids, and its relation to the experimentally demonstrated high in vitro bioactivities of these materials is discussed.
Place, publisher, year, edition, pages
2008. Vol. 112, no 14, 5552-5562 p.
Nuclear-Magnetic-Resonance, H-1 MAS NMR, IN-Vitro, Calcium-Phosphate, Gel Glasses, Silica Nanoparticles, Cross-Polarization, Apatite Formation, Spinning NMR, System
IdentifiersURN: urn:nbn:se:su:diva-15705DOI: 10.1021/jp7107973ISI: 000254710800045OAI: oai:DiVA.org:su-15705DiVA: diva2:182225