Structural, dissolution, and dynamic properties of binary (1-x)SiO2-xCaO melt-derived bioactive glasses using computational simulation analysis

Molecular dynamics (MD) simulations provide valuable insights into the structural and dissolution behaviors of silicate-based bioactive glasses (BGs) at the atomic scale. The samples were simulated in this study with composition of 40SiO₂-60CaO (40S), 50SiO₂-50CaO (50S), 60SiO₂-40CaO (60S), 70SiO₂-30CaO (70S), and 80SiO₂-20CaO (80S) (mol%). Buckingham and Coulomb potentials were used for short- and long-range interactions, respectively. Based on the results, the average Si–O-Si angles in 40S were 4.6°smaller than those in 80S, showing less tetrahedral freedom at higher CaO contents. Additionally, owing to the lowest CaO content, 80S had the highest Q⁴ at 57%, showing the highest network connectivity (NC) of 3.5, resulting in the lowest solubility. In contrast, 40S had the highest density of 2.91(g/cm³), which was attributed to the higher molar mass of CaO. According to ICP-AES results, 40S had the highest initial Si concentration (39∓1.8 ppm) after 1 day in a simulated body fluid (SBF) solution. These findings show how compositional changes influence the structure and dissolution behavior of binary BGs. Taken together, 60S had optimized integrity between structural and solubility properties owing to its NC of 2.67, suggesting it to be an optimal specimen for biomedical applications.