The incorporation of
yttrium in bioactive glasses (BGs) could lead to a new generation of
radionuclide vectors for
cancer therapy, with high biocompatibility, controlled biodegradability and the ability to enhance the growth of new healthy tissues after the treatment with
radionuclides. It is essential to assess whether and to what extent
yttrium incorporation affects the favourable properties of the BG matrix: ideally, one would like to combine the high surface reactivity typical of BGs with a slow release of radioactive
yttrium. Molecular Dynamics simulations show that, compared to a BG composition with the same
silica fraction, incorporation of
yttrium results in two opposing effects on the glass durability: a more fragmented
silicate network (leading to lower durability) and a stronger
yttrium-mediated association between separate
silicate fragments (leading to higher durability). The simulations also highlight a high site-selectivity and some clustering of
yttrium cations, which are likely linked to the observed slow rate of
yttrium released from related Y-BG compositions. Optimisation of
yttrium BG compositions for
radiotherapy applications thus depends on the delicate balance between these effects.