Toward a Rational Design of Bioactive Glasses with Optimal Structural Features: Composition-Structure Correlations Unveiled by Solid-State NMR and MD Simulations
2014 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 118, no 3, 833-844 p.Article in journal (Refereed) Published
The physiological responses of silicate-based bioactive glasses (BGs) are known to depend critically on both the P content (np) of the glass and its silicate network connectivity ((N) over bar (SI)(BO)). However, while the bioactivity generally displays a nonmonotonic dependence on np itself, recent work suggest that it is merely the net orthophosphate content that directly links to the bioactivity. We exploit molecular dynamics (MD) simulations combined with P-31 and Si-29 solid-state nuclear magnetic resonance (NMR) spectroscopy to explore the quantitative relationships between (N) over bar (SI)(BO), npand the silicate and phosphate speciations in a series of Na2O-CaO-SiO2-P2O5 glasses spanning 2.1 <=(N) over bar (SI)(BO) <= 2.9 and variable P2O5 contents up to 6.0 mol %. The fractional population of the orthophosphate groups remains independent of np at a fixed (N) over bar (SI)(BO)-value, but is reduced slightly as (N) over bar (SI)(BO) increases. Nevertheless, P remains predominantly as readily released orthophosphate ions, whose content may be altered essentially independently of the network connectivity, thereby offering a route to optimize the glass bioactivity. We discuss the observed composition-structure links in relation to known composition-bioactivity correlations, and define how Na2O-CaO-SiO2-P2O5 compositions exhibiting an optimal bioactivity can be designed by simultaneously altering three key parameters: the silicate network connectivity, the (ortho)phosphate content, and the n(Na)/n(ca) molar ratio.
Place, publisher, year, edition, pages
2014. Vol. 118, no 3, 833-844 p.
Research subject Physical Chemistry
IdentifiersURN: urn:nbn:se:su:diva-101004DOI: 10.1021/jp409652kISI: 000330252700020OAI: oai:DiVA.org:su-101004DiVA: diva2:699701