Effect of B/Si molar ratio on the structure and properties of borosilicate bioactive glasses assessed using molecular dynamics simulations.

Due to the improvement and innovation of theoretical methods and the increasing enhancement of high performance computing, computer simulations provide a new method and strategy for optimizing complex composition of novel BG. In this work, molecular dynamics (MD) simulations were used to analyze the effect of B/Si molar ratio on the structure of borosilicate bioactive glass (BBG) and to investigate the effect of structural alterations on its ions release and biological effects. Structural descriptor Fnet was calculated from the simulated data, and the linear relationships of Fnet with B and Mg releasing rate in deionized water and simulate body fluid (SBF) were built. In vitro mineralization experiments showed that all three BBGs could generate hydroxyapatite and the release of some network modifier ions such as Mg would be regulated by the B/Si ratio. In vitro cellular experiments revealed that the BBG sample with a composition of 1.25B (6Na2O-8K2O-8MgO-22CaO-22.5B2O3-2P2O5-31.5SiO2) promoted the proliferation and osteogenic differentiation of rat bone marrow mesenchymal stem cells, and significantly enhanced the expression of osteogenesis-related genes such as OPN, which might be related to the release of Mg at an early stage.