In vitro susceptibility of filamentous fungi to copper nanoparticles assessed by rapid XTT colorimetry and agar dilution method

Objective. - Metal nanoparticles and their uses in various aspects have recently drawn a great deal of attention. One of the major applications is that it can be used as an antimicrobial agent. They can be considered in approaches targeted to decrease the harms caused by microorganisms, specifically fungi, threatening the medical and industrial areas. The aim of this study was to investigate the antifungal activity of synthesized copper nanoparticles (CuNPs) against four filamentous fungi including Alternaria alternata, Aspergillus flavus, Fusarium solani, and Penicillium chrysogenum. Material and methods. - Zerovalent copper nanoparticles of mean size 8 nm were synthesized by inert gas condensation (IGC) method. The antifungal activity of these synthesized copper nanoparticles was measured against selected fungi by using two different techniques including agar dilution method and XTT reduction assay. Results. - The minimal inhibitory concentrations (MICs) for copper nanoparticles by agar dilution method were less or equal to 40 mg/L for P. chrysogenum, less or equal to 60 mg/L for A. alternata, less or equal to 60 mg/L for E solani, and less or equal to 80 mg/L for A. flavus. And also MICs obtained by XTT reduction assay ranged from 40 to 80 mg/L. Conclusion. - Our data demonstrated that the copper nanoparticles inhibited fungal growth, but the fungal sensitivity to copper nanoparticles varies depending on the fungal species. Therefore, it is advisable that the minimal inhibitory concentrations (MICs) be examined before using these compounds. It is hoped that, in future, copper nanoparticles could replace some antifungal agents, making them applicable to many different medical devices and antimicrobial control system. (C) 2012 Elsevier Masson SAS. All rights reserved.