Development of functional borate glass surfaces to inhibit bacterial growth

A variety of borate glass compositions are shown to be effective in inhibiting bacterial growth on their surfaces. Both Gram-negative (Escherichia coli and Salmonella typhimurium) and Gram-positive bacteria (Stapphylococcus aureus) were effectively killed by lithium borate and lithium potassium borate glasses of high and low alkali contents. The surface environment was shown to become acidic for low metal contents, halting growth, and alkaline for higher metal contents. The alkaline surface layer proved to be more efficient in eliminating bacteria. The more alkaline sample also appeared to act especially rapidly in preventing growth. Micro-Raman measurements were taken to characterise the surface layer responsible for the bacterial inhibition.