Green synthesis of silver nanoparticles from shallot extract for potent antifungal activity enhanced by blue diode laser irradiation against candida albicans

This study aims to evaluate the efficacy of photodynamic therapy (PDT) using a 405 nm laser and two photosensitizers derived from silver nanoparticles, red onion extract, and shallot peel extract, comparing their effectiveness against Candida albicans. Candida albicans causes candidiasis, which requires effective, chemical-free treatment methods. PDT offers promise in this regard. The samples were divided into four groups: B1 (silver nanoparticles from red onion extract at concentrations of 1 mM, 1.5 mM, and 2 mM), A1 and A2 (fungus samples irradiated with a 405 nm laser at varying times and concentrations), and B2 (silver nanoparticles from shallot peel extract at the same concentrations). After each photosensitizer exposure, the fungi were subjected to radiation for 90–180 s. Following incubation, optical density (OD) was measured, and Tukey's Post Hoc Test (p < 0.05) and Two-Way ANOVA were used for statistical analysis. Silver nanoparticles from shallot and red onion peel extracts and 405 nm laser radiation dramatically decreased the viability of Candida albicans compared to controls. After 180 s of radiation, red onion extract nanoparticles showed reductions of 50.92% to 64.55%, and shallot peel extract nanoparticles showed reductions of 47.37% to 70.71%. Using an energy density of 3.44 J/cm², red onion and shallot peel extract nanoparticles effectively deactivated C. albicans, with red onion extract achieving up to 70.71% ± 1.99% reduction. The study highlights the potential of PDT with silver nanoparticles as an alternative treatment for Candida infections.