Formation of hydroxyapatite on surface of SiO2– P2O5–CaO–SrO–ZnO bioactive glass synthesized through sol-gel route

Abstract

Abstract The bioactive glass (BG) system of 60SiO2–4P2O5–31CaO-xSrO-(5-x) ZnO (0 ≤ x ≤ 5 %mol) was synthesized by sol-gel route. The role of zinc contents and strontium on the in-vitro formation of hydroxyapatite (HA), antibacterial properties, and cell viability of BGs were investigated. XRD (X-ray diffraction analysis), SEM (Scanning electron microscopy) and FTIR (Fourier transform infrared spectroscopy) were utilized to study the HA morphology, its functional groups and obtained phases, respectively. The results established the formation of HA on the surface of strontium and zinc-containing BGs. The 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay after one day immersion in SBF, implied that the viability of samples containing 4 %mol Sr and 1 %mol Zn (S4-Z1) and 3 %mol Sr and 2 %mol Zn (S3-Z2) increases by increasing immersion time, while the sample containing 1 %mol Sr and 4 %mol Zn (S1-Z4) showed a statistically significant increase in osteoblast G292 proliferation. Furthermore, the antibacterial tests showed that all Zn containing BGs created clear inhabitation zones. The zone of clearance around the bioactive glasses demonstrated that sufficient Zn ion was released to create an antibacterial activity around the bioactive glasses.