Protein Adsorption on SiO₂-CaO Bioactive Glass Nanoparticles with Controllable Ca Content

Bioactive glass nanoparticles (BGNs) are emerging multifunctional building blocks for various biomedical applications. In this study, the primary aim was to develop monodispersed binary SiO₂-CaO BGNs with controllable Ca content. We successfully synthesized such spherical BGNs (size ~110 nm) using a modified Stöber method. Our results showed that the incorporated Ca did not significantly affect particle size, specific surface area, and structure of BGNs. Concentrations of CaO in BGN compositions ranging from 0 to 10 mol% could be obtained without the gap between actual and nominal compositions. For this type of BGNs (specific surface area 30 m²/g), the maximum concentration of incorporated CaO appeared to be ~12 mol%. The influence of Ca content on protein adsorption was investigated using bovine serum albumin (BSA) and lysozyme as model proteins. The amount of adsorbed proteins increased over time at the early stage of adsorption (<2 h), regardless of glass composition and protein type. Further incubation of BGNs with protein-containing solutions seemed to induce a reduced amount of adsorbed proteins, which was more significant in BGNs with higher Ca content. The results indicate that the Ca content in BGNs is related to their protein adsorption behavior.