Antimicrobial effect of nanometric bioactive glass 45S5

Abstract

Most recent advances in nanomaterials fabrication have given access to complex materials such as SiO2-Na2O-CaO-P 2O5 bioactive glasses in the form of amorphous nanoparticles of 20- to 60-nm size. The clinically interesting antimicrobial properties of commercially available, micronsized bioactive glass 45S5 have been attributed to the continuous liberation of alkaline species during application. Here, we tested the hypothesis that, based on its more than ten-fold higher specific surface area, nanometric bioactive glass releases more alkaline species, and consequently displays a stronger antimicrobial effect, than the currently applied micron-sized material. Ionic dissolution profiles were monitored in simulated body fluid. Antimicrobial efficacy was assessed against clinical isolates of enterococci from persisting root canal infections. The shift from micron- to nano-sized treatment materials afforded a ten-fold increase in silica release and solution pH elevation by more than three units. Furthermore, the killing efficacy was substantially higher with the new material against all tested strains.