Synthesis, characterisation and antifungal activity of chemically and fungal-produced silver nanoparticles against Trichophyton rubrum

Aims To characterise and explore the potential in extracellular biosynthesis of silver nanoparticles (AgNPs) by Penicillium chrysogenum and Aspergillus oryzae and to investigate the antifungal effect of chemically vs. biologically synthesised AgNPs comparing with conventional antifungal drugs against Trichophyton rubrum. Methods and Results Chemically synthesised AgNPs (Chem-AgNPs) coated with polyvinylpyrrolidone (PVP) were synthesised by chemical reduction method with glucose in PVP aqueous solution. Biologically synthesised AgNPs (Bio-AgNPs) were produced from the extracellular cell-free filtrate of Penicillium chrysogenum MUM 03.22 and Aspergillus oryzae MUM 97.19. Among the commercial antifungal drugs terbinafine exhibited the lower MIC range values of 0.063 to 0.25 μg ml-1 for the clinical strains. Chem-AgNPs exhibited antifungal activity against all T. rubrum strains. Bio-AgNPs produced by the fungal cell-free filtrate of P. chrysogenum showed an antifungal activity higher than fluconazole but less than terbinafine, itraconazole and Chem-AgNPs. Conclusion The synthesis parameters in future works should be carefully studied to take full advantage of all the potential of filamentous fungi in the synthesis of AgNPs. Significance and Impact of the study: Bio-AgNPs could be used as antifungal agents, namely against dermatophytesThe authors thank Pedro Martins (Physics Department of University of Minho) for help in XRD analysis. The authors thank to SDBSWeb: http://sdbs.db.aist.go.jp (Japanese National Institute of Advanced Industrial Science and Technology). The authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013. Nicolina Dias acknowledges the project 'Consolidating Research Expertise and Resources on Cellular and Molecular Biotechnology at CEB/IBB', RECI/BBB-EBI/0179/2012