Visible light-enhancing antibacterial ability of gold ions for its application of the prevention and treatment of dentin caries

Abstract

To develop new antimicrobial strategy or agents has always been an eternal topic for the researchers. In this study, we have found that the visible light can enhance the antibacterial action of gold ions because of the photo-reduction and thus the visible light energy can be used to kill bacteria. The electron accepting ability of Au ions exposed to the visible light can strengthen, so their damage capability for the organic compounds from bacteria simultaneously enhances. The products of light-triggering Au ions, Au nanoparticles (Au NPs), also can bind protein and other bacterial cell wall components to further enhance the antibacterial ability. With the aid of the penetrating capacity of Au ions and light, light can also enhance the antibacterial action of Au ion in the biofilm and dentinal tubules and their products have the ability to crosslink the collagens to protect them from the degradation of collagenase. The toxicity of Au ions limits its application in clinic treatment, but the toxicity can decrease significantly after Au ions kills bacteria and the light can further reduce the toxicity as well. High concentration of Au ions and long-exposure light for dentin-pulp complex also are safe in vivo. Hence, light-enhancing the antibacterial treatment of Au ions has the potential to be used in the prevention and cure of the caries.