Evaluation of Three Borate-Bioactive Glass Compositions for Antibacterial Applications

Abstract

The prevalence of cases of antibiotic resistant infections and the limited number of new antibiotics call for new strategies to prevent bacterial infections. In this study, we evaluate the effectiveness of three different compositions of bioactive glass, doped with silver as an antimicrobial agent for potential applications in preventing bacterial infections. The different glasses were formulated to dissolve and release silver at different rates enabling their use in different applications either individually or in combination to achieve a desired effect. Silver oxide (Ag 2 O) was incorporated into various glass formulations and antibacterial effectiveness was measured using radius of inhibition. Each silver-doped glass effectively inhibited the growth of Escherichia coli , Staphylococcus aureus and Pseudomonas aeruginosa with radius of inhibition correlating directly with the dissolution rate of the glass—the faster dissolving glass producing the larger radius of inhibition. Suspending particles of the silver containing glass in phosphate buffered saline or fetal calf serum, slowed the dissolution of each glass and extended the effectiveness of the silver containing glass over time (based on size of the radius of inhibition) compared to water. Potential applications of the powdered glass formulations would be to incorporate glasses with different properties into coatings or cosmetics. To investigate the feasibility of these applications, the silver-glass powder was incorporated into polycaprolactone polymer to determine the antibacterial properties of the imbedded glass powder. Based on this investigation, the silver glass formulations reported herein have potential applications in the medical device, dental, pharmaceutical and cosmetic industries.