Silver nanoparticle production by the fungus Fusarium oxysporum: nanoparticle characterisation and analysis of antifungal activity against pathogenic yeasts

Abstract

The microbial synthesis of nanoparticles is a green chemistry approach that combines nanotechnology and microbial biotechnology. The aim of this study was to obtain silver nanoparticles (SNPs) using aqueous extract from the filamentous fungus Fusarium oxysporum as an alternative to chemical procedures and to evaluate its antifungal activity. SNPs production increased in a concentration-dependent way up to 1 mM silver nitrate until 30 days of reaction. Monodispersed and spherical SNPs were predominantly produced. After 60 days, it was possible to observe degenerated SNPs with in additional needle morphology. The SNPs showed a high antifungal activity against Candida and Cryptococcus , with minimum inhibitory concentration values ≤ 1.68 µg/mL for both genera. Morphological alterations of Cryptococcus neoformans treated with SNPs were observed such as disruption of the cell wall and cytoplasmic membrane and lost of the cytoplasm content. This work revealed that SNPs can be easily produced by F. oxysporum aqueous extracts and may be a feasible, low-cost, environmentally friendly method for generating stable and uniformly sized SNPs. Finally, we have demonstrated that these SNPs are active against pathogenic fungi, such as Candida and Cryptococcus .

Antimicrobial Activity of Green Silver Nanoparticles against Fluconazole-resistant Candida albicans in Animal Model

“…The combination between AgNPs and FLC had a marked reduction in FLC MIC value (8/2.17 µg/ ml). Our results was in accordance with Ishida et al (2014), who reported a fungicidal effect of green AgNPs on C. albicans, with MIC and MFC values of 1.68 and 3.40 μg/ml, respectively. No cytotoxic effect was shown up to a concentration of 10 μg/ml of AgNPs for Hep-2 cells (Marcato et al, 2013 andLima et al, 2013).…”

Microbe‐Mediated Extracellular and Intracellular Mineralization: Environmental, Industrial, and Biotechnological Applications

“…Fungi such as Pythium aphanidermatum , [ 225 ] Fusarium oxysporum , [ 226 ] Epicoccum nigrum , [ 246 ] and Schizophyllum commune [ 227 ] have been used for green synthesis of AgNPs. [ 247 ] Similar to AuNPs, the mechanism of fungi‐mediated synthesis of AgNPs involves reduction of Ag + to Ag 0 by the metabolites released by the fungi.…”

“…[ 225 ] Stabilization of AgNPs to prevent their aggregation may be achieved via a protective coating. [ 226 ] Humic acid has been reported to function as a reducing agent for the synthesis of AgNPs at room temperature and as a capping agent to enhance the colloidal stability of the nanoparticles by preventing them from aggregating into a larger mass of silver. [ 248 ] Compared with chemically synthesized nanoparticles, biogenic AgNPs are generally less toxic to the human body.…”

Green synthesis of silver nanoparticles: biomolecule-nanoparticle organizations targeting antimicrobial activity

“…Green synthesized AgNPs showed a high level of antifungal activity against Candida and Cryptococcus, with minimum inhibitory concentration values # 1.68 mg ml À1 for both genera. 224 It has been investigated using disc diffusion method that colloidal silver has strong antifungal activity against three species of Candida like C. albicans, C. glabrata and C. tropicalis. 225 Silver nanoparticles synthesized from Pilimelia columellifera subsp.…”