Effect of CaO on the dissolution property, surface zeta potential and antibacterial properties of ZnO–Na₂O–B₂O₃–SiO₂ glass system

In this study, we analyzed the correlation between the glass composition and properties of ZnO-containing borosilicate glasses. 20Na₂O–30ZnO–xB₂O₃–(50-x)SiO₂ (x = 10, 20, 30, 40 mol%) glasses were prepared to analyze the relationship between the dissolution characteristics and antibacterial properties. Na₂O was substituted with 5 and 10 mol% of CaO in 20Na₂O–30ZnO–10B₂O₃–40SiO₂ and 20Na₂O–30ZnO–40B₂O₃–10SiO₂ glasses to determine the relationship between the zeta potential and antibacterial properties. More Zn²⁺ ions were released in the B₂O₃-rich composition than that the SiO₂-rich composition. The antibacterial activity improved with increasing B₂O₃ concentration. The surface zeta potentials of the glass with CaO became more positive, and the antibacterial activity improved dramatically. The composition with the lowest SiO₂/B₂O₃ ratio exhibited the highest dissolution rate and 99.9% antibacterial activity. In addition, 10CaO–10Na₂O–30ZnO–40SiO₂–10B₂O₃ glass showed 99.9% antibacterial activity, despite the limited release of Zn²⁺ ions. Hence, it was deduced that the antibacterial activity could be improved by controlling the surface zeta potential of the glasses.