title: Molecular dynamics simulations and structural descriptors of radioisotope glass vectors for in situ radiotherapy.
abstract: The low solubility (high durability) of yttrium aluminosilicate (YAS) glass is one of its most important properties for use in in situ radiotherapy. Simple parameters, such as silica or yttria content or network connectivity, are not sufficient to rationalize the dependence of the solubility on the glass composition observed experimentally. We performed classical molecular dynamics (MD) simulations of eight different YAS glasses of known solubility and analyzed the MD trajectories to identify specific structural features that are correlated and can be used to predict the solubility. We show that the (Si-)O-Si coordination number CN(SiOSi), the yttrium-yttrium clustering ratio R(YY), and the number of intratetrahedral O-Si-O bonds per yttrium atom N(intra) can be combined into a single structural descriptor s = f(CN(SiOSi),R(YY),N(intra)) with a high correlation with the solubility. The parameter s can thus be calculated from MD simulations and used to predict the solubility of YAS compositions, allowing one to adjust them to the range required by radiotherapy applications. For instance, its trend shows that high-silica- and low-yttria-content YAS glasses should be sufficiently durable for the radiotherapy application, although additional clinical considerations may set a lower limit to the yttria content.
authors.affiliation: Department of Chemistry and Thomas Young Centre, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
authors.forename: Jamieson K
authors.initials: JK
authors.lastname: Christie
authors.forename: Antonio
authors.initials: A
authors.lastname: Tilocca
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry* / Q000627:therapeutic use; D005898:Glass / Q000737:chemistry; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D011838:Radiation-Sensitizing Agents / Q000737:chemistry* / Q000627:therapeutic use; D012995:Solubility; D015019:Yttrium / Q000737:chemistry* / Q000627:therapeutic use
chemical_list: D000538:Aluminum Silicates; D011838:Radiation-Sensitizing Agents; C049037:aluminosilicate; D015019:Yttrium