Eradication of Fungi Using MoSe<sub>2</sub>/Chitosan Nanosheets
Sanchari Saha, Matthew S. Gilliam, Qing Hua Wang, Alexander A. Green
Abstract
Antifungal drug resistance is an increasingly significant threat to humans, livestock, and crops. Recent studies have shown nanomaterials as promising alternatives in combating drug-resistant pathogens. Here, we show that molybdenum diselenide (MoSe2) nanosheets dispersed in the cationic polymer chitosan (CS) exhibit exceptional antifungal activity. The MoSe2/CS nanosheets provide minimum inhibitory concentrations (MICs) between 0.78 and 37.5 μg ml–1 against a variety of unicellular fungal strains and demonstrate minimum fungicidal concentrations (MFCs) from 0.5 to 75 μg ml–1 for diverse unicellular and filamentous strains. Furthermore, we demonstrate the ability of MoSe2/CS to eradicate increasingly prevalent and highly multi-drug-resistant (MDR) fungi Candida auris strains with MICs of 25 to 50 μm ml–1 and MFCs of 37.5 to 150 μm ml–1. The effective antifungal activity of MoSe2/CS was observed after an incubation time of 3 h, which is faster than the time needed for other nanomaterial-based antifungal agents incorporating graphene, two-dimensional (2D) nanomaterials, or silver nanoparticles. MoSe2/CS also showed high biocompatibility and was benign toward human red blood cells and human embryonic kidney cells. Electron microscopy and confocal optical microscopy show that fungal cells treated with MoSe2/CS nanosheets exhibit morphological deformities, ruptured cell walls and interior voids, and metabolic inactivation. Mechanistic investigations revealed that treatment with MoSe2/CS triggers complete membrane depolarization and membrane disintegration within 3 h. Hence, this work demonstrates that the biocompatible nanomaterial MoSe2/CS is a highly effective alternative antifungal agent against many kinds of pathogenic fungi including MDR strains.