Synthesis, Characterization, and In Vitro Bioactivity of Sol-Gel-Derived SiO₂–CaO–P₂O₅–MgO-SrO Bioactive Glass

Abstract

In this study, the synthesis of SiO₂–CaO–P₂O₅–MgO-SrO bioactive glass was performed by the sol-gel method. Sol-gel-derived bioactive glass material was produced both in powder and in discs form by uniaxial pressing, followed by sintering at 700°C. The obtained material was evaluated by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM). Cytocompatibility of ionic products of the bioactive glass were assessed using MTT assay and direct contact test. The surface reactivity of the resultant bioactive glass specimens was analyzed by immersion studies in simulated body fluid (SBF) for different time intervals while monitoring the concentration of silicon, calcium, phosphorus, strontium, and magnesium in the SBF medium. The SEM, XRD, and FTIR studies were conducted before and after soaking of the material in SBF. At first, an amorphous calcium phosphate was formed; after 7 days this surface consisted of deposited crystalline apatite. In vitro experiments with human osteosarcoma cell lines (MG-63) indicated that bioactive glass incorporating a limited amount of magnesium and strontium in the composition stimulates bone cell production of alkaline phosphatase. Finally, this material proved to be non-toxic and compatible for the proposed work in segmental defects in the goat model in vivo.

Keywords:

• Bioactive glass
• osteoblast like cells
• SBF
• sol-gel

Acknowledgments

This study was part of a PhD thesis supported by Tehran University of Medical Sciences (grant No: 91-03-70-19292).