Dr Jamieson Christie is a lecturer in the Department of Materials at Loughborough University, a post he took up in 2015 after research positions at University College London and The Abdus Salam International Centre for Theoretical Physics in Trieste, and a PhD at the University of Cambridge. His research interests are in the computer simulation of glass, particularly biomedically relevant compositions. Much of a particular composition’s suitability for biomedical implantation can be understood from a characterization of its atomic structure and Jamie has used a range of computational techniques to improve our understanding of these connections.
Nanoheterogeneity in fluoridated bioactive glass
Haaris Navid and Jamieson K. Christie*
Department of Materials, Loughborough University, Loughborough, LE11 3TU
Bioactive glass bonds chemically to bone and soft tissue. It has very wide applications in healthcare, particularly in bone repair. The glass is silicate-based, but also contains Na2O, CaO and, in some cases, various ions of therapeutic value, such as fluorine. A recent review , based on work presented at a previous Turner Symposium, has discussed the experimental and computational evidence for the formation of structural nanoheterogeneity in the form of atomic clustering caused by the inclusion of fluorine into the glass.
Here, we present the results of classical molecular dynamics simulations of a range of different compositions of bioactive glass, based on the 45S5 composition, concentrating particularly on the effect of changes to the fluoride and phosphate content. Both fluorine and phosphorus species cluster in the glass, implying the formation of structural nanoheterogeneities. The clustering of these two atomic species is enhanced when they are present in the glass at low concentration. Other ions, such as calcium, do not seem to cluster at any bioactive composition.
In this presentation, we will characterize the structure of the glasses thoroughly, including the extent and compositional dependence of any clustering, and discuss the consequences for the bioactivity of the glass.
 J. K. Christie, D. S. Brauer, Phys. Chem. Glasses 58, 180 (2017)