Mechanism of Action of Green-Synthesized Silver Nanoparticle-Incorporated Dental Varnish Against Candida albicans

Abstract

Introduction: Candida albicans , a common fungal pathogen, is often associated with oral infections such as denture stomatitis. Dental varnishes, especially those incorporating antimicrobial agents, have shown promise in preventing C. albicans colonization. This study investigates the antifungal efficacy of a dental varnish incorporating green-synthesized silver nanoparticles (AgNPs) using Ocimum gratissimum and Ocimum tenuiflorum extracts. Materials and methods: AgNPs were synthesized via a green synthesis method using Ocimum extracts. The AgNPs were then incorporated into a dental varnish. The antifungal efficacy of the AgNP-incorporated varnish was evaluated against C. albicans using various assays, including agar well diffusion, time-kill curve, protein leakage, and cytoplasmic leakage analyses. Results: The AgNP-incorporated dental varnish demonstrated significant antifungal activity against C. albicans . The agar well diffusion assay showed a dose-dependent increase in the zone of inhibition, with the highest concentration (100 µg/mL) achieving a zone of 23 mm. The time-kill curve assay indicated a concentration-dependent reduction in colony-forming units (CFU) of C. albicans , with the highest concentration resulting in a CFU reduction to below 10 3 within five hours. Both protein and cytoplasmic leakage analyses confirmed membrane disruption, showing increased optical density readings at higher concentrations of AgNPs. Discussion: The results suggest that the antifungal activity of the AgNP-incorporated dental varnish is mediated through multiple mechanisms, including membrane disruption, increased permeability leading to protein and cytoplasmic leakage, and possibly the generation of reactive oxygen species (ROS). The varnish's efficacy was comparable to that of commercial antifungal dental varnishes, highlighting its potential as a viable alternative in dental applications. Conclusion: Green-synthesized AgNPs, when incorporated into dental varnish, exhibit potent antifungal activity against C. albicans . The study demonstrates that this approach can effectively disrupt fungal cells, suggesting its potential use in preventing and treating oral fungal infections. Future research should explore the in vivo efficacy, safety, and long-term stability of AgNPs in dental varnish formulations.