Investigation on structure-property relationships of MgO-SrO containing silicate-based bioactive glasses: An...

Molecular dynamics (MD) simulations and experimental analysis were performed on MgO-SrO containing bioactive glasses (MSBGs) with the composition of 60SiO₂-(31-x)CaO-4P₂O₅-5MgO-xSrO (mol%) (x = 0, 1, 3, 5, 8, 10, 15, 20; M5S0-M5S20) to evaluate the structural properties, ion clustering, and dissolution behavior as a function of SrO content. Simulation employed the Buckingham potential for short-range interactions and Coulombic potentials for long-range forces. MSBGs had Si-O and P-O bond lengths of 1.609 Å and 1.491 Å, with O-Si-O and O-P-O bond angles centered at ∼109.3° and 109.4°, respectively, confirming tetrahedral SiO₄/PO₄ coordination. Across all compositions, Si-O-Si bonds dominated the majority of the distribution (88-89 %), with Si-O-P at 11-12 % and P-O-P negligible (∼0.3 %). Densities decreased from 2.913 g·cm^-3 (M5S20) to 2.631 g·cm^-3 (M5S0), reflecting network loosening with SrO substitution. Qⁿ distribution remained stable, with Q³/Q⁴ fractions of 38-43 % and 26-30 % for Si-based tetrahedra. R-factor analysis revealed optimal homogeneity for M5S5 (R_Si/P^Sr = 0.838252), balancing reduced cation clustering and moderate network stability. ICP-AES showed M5S5 with a sustained release of Si⁴⁺, Mg²⁺, and Sr²⁺ over 24 h. Meanwhile, antibacterial study resulted in statistically significant increase in efficiency for M5S5 compared to M5S0 (***p < 0.001). The combined computational and experimental findings identify M5S5 as the most promising candidate for biomedical applications requiring structural benefits, controlled ion release, and antibacterial efficiency.