Integrating biological activity into radioisotope vectors: molecular dynamics models of yttrium-doped bioactive glasses

Abstract

Yttrium-containing bioactive glasses (YBGs) have the potential to extend the function of inert glass vectors for in situ radiotherapy, integrating it with the biodegradability and the ability to stimulate growth of new tissues. Combining these properties with the required low radioisotope dissolution rates requires a detailed understanding of the effect of yttrium on the structure of these materials. Molecular dynamics simulations of a range of YBG compositions with favourable network connectivity allowed us to extract relevant structural descriptors which affect the performances of these glasses in radiotherapy. We focus in particular on the density and strength of the network of non-covalent crosslinks built by Na, Ca and Y cations and on the ion clustering behaviour; we show that it should be possible to employ YBGs containing higher amounts of yttrium as radioisotope vectors, due to the increasingly stronger glass network which will limit the overall ion dissolution rates, without inhibiting the glass bioactivity.