Exploring processing–structure–property relationships of chemically precipitated strontium silicate particles for medical applications†

Bone regeneration in the presence of osteoporosis presents a significant challenge in dental and orthopedic surgery. To tackle this issue, researchers have developed strontium-containing biomaterials. However, preventing bacterial infection is also crucial for successful surgical treatment. In this study, we delved deep into the processing to tailor the composition and structure of new strontium silicates with unique properties to address this challenge. We used chemical precipitation to prepare various strontium silicate particles using varying ammonia concentrations and Sr/Si precursor ratios. The L929 cytotoxicity, differentiation of human mesenchymal stem cells (hMSCs), biological function of RAW 264.7 macrophages, and antibacterial activity against E. coli and S. aureus were evaluated. As a result, higher ammonia concentration led to the formation of SrSiO₃ and Sr₂SiO₄ particles with smaller sizes and higher Sr/Si ratios. These particles exhibited increased antibacterial efficacy and radiopacity, promoting cell viability and osteogenic activity of hMSCs and modulating M1/M2 macrophage polarization. In conclusion, the developed strontium silicate demonstrated superior antibacterial activity, exceptional osteogenic properties, and clear visibility during procedures, making it a promising material for bone regeneration and osteoporosis treatment.