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Published on: February 14, 2018
Antifungal Activity of Mycogenic Silver Nanoparticles on Clinical Yeasts and Phytopathogens
Luiz Gustavo Ribeiro1,2, Gabriella Sales Calaço Roque1,2, Rafael Conrado1
1Development and Innovation Laboratory, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo 05503-900, SP, Brazil.
Abstract:
In this study, seven different silver nanoparticles (AgNPs) were obtained using the fungi species from the phylum Ascomycota, Aspergillus tubingensis, Aspergillus spp., Cladosporium pini-ponderosae, Fusarium proliferatum, Epicoccum nigrum, Exserohilum rostratum, and Bionectria ochroleuca, isolated from the Brazilian biodiversity, particularly from the mangrove and Caatinga biomes. The nanoparticles were coded as AgNP-AT, AgNP-Asp, AgNP-CPP, AgNP-FP, AgNP-EN, AgNP-ER, and AgNP-BO and characterized using spectrophotometry (UV-Vis), dynamic light scattering (DLS), zeta potential, transmission electron microcopy (TEM), and Fourier-transform infrared (FTIR) spectroscopy. All the AgNPs presented homogeneous size in the range from 43.4 to 120.6 nm (DLS) and from 21.8 to 35.8 nm (TEM), pH from 4.5 to 7.5, negative charge, and presence of protein coating on their surface. The antifungal activity of the AgNPs was evaluated on clinical strains of Candida albicans, and on the non-albicans species, Candida krusei, Candida glabrata, Candida parapsilosis, Candida tropicalis, and Candida guilliermondii, common in hospital infections, and against the phytopathogens Fusarium oxysporum, Fusarium phaseoli, Fusarium sacchari, Fusarium subglutinans, Fusarium verticillioides, and Curvularia lunata, which are species responsible for serious damage to agriculture production. The AgNPs were effective against the yeasts with MICs ranging from 1.25 to 40 µM and on the phytopathogens with MICs from 4 to 250 µM, indicating the promising possibility of application of these AgNPs as antifungal agents. The results indicated that the physicochemical parameters of the AgNPs, including the functional groups present on their surface, interfered with their antifungal activity. Overall, the results indicate that there is no specificity of the AgNPs for the yeasts or for the phytopathogens, which can be an advantage, increasing the possibility of application in different areas.
Insights
Seven fungal-derived silver nanoparticles (AgNPs) show broad-spectrum antifungal activity against human and plant pathogens. Physicochemical properties influence their effectiveness, suggesting diverse applications.
Area of Science:
- Nanotechnology
- Mycology
- Biochemistry
Background:
- Fungal biodiversity in Brazilian mangrove and Caatinga biomes offers novel sources for biosynthesis.
- Silver nanoparticles (AgNPs) are increasingly explored for antimicrobial applications.
Purpose of the Study:
- To synthesize and characterize AgNPs using seven Ascomycota fungi species.
- To evaluate the antifungal efficacy of these AgNPs against clinical yeast strains and phytopathogenic fungi.
Main Methods:
- AgNPs synthesis via fungal extracts, followed by characterization using UV-Vis, DLS, zeta potential, TEM, and FTIR.
- Antifungal activity testing using minimum inhibitory concentration (MIC) assays against Candida spp. and Fusarium/Curvularia spp.
Main Results:
- Seven AgNPs (AgNP-AT, AgNP-Asp, AgNP-CPP, AgNP-FP, AgNP-EN, AgNP-ER, AgNP-BO) were successfully synthesized with sizes ranging from 21.8–120.6 nm.
- AgNPs exhibited broad-spectrum antifungal activity, with MICs from 1.25–40 µM for yeasts and 4–250 µM for phytopathogens.
- Physicochemical properties, including surface functional groups, correlated with antifungal potency, and no specific target preference was observed.
Conclusions:
- Fungi from Brazilian biodiversity can be utilized for green synthesis of AgNPs with significant antifungal properties.
- These AgNPs demonstrate potential as versatile antifungal agents for both clinical and agricultural applications.
- Further research into structure-activity relationships can optimize AgNP design for targeted antifungal therapies.
