Development of a new biomimetic method for the synthesis of silver nanoparticles based on fungal metabolites: optimization and antibacterial activity

Abstract

AbstractBACKGROUNDA biomimetic method was developed for the synthesis of silver nanoparticles (AgNPs). Synthetic chemical compounds were used according to the metabolites present in the fungal extracts for the synthesis of AgNPs. The main objective of this study was to find a simple and effective synthesis method without the presence of a living organism.METHODOLOGYA central composite design combined with response surface methodology was used to optimize the necessary metabolite concentrations (flavin adenine dinucleotide (FAD), hydroquinone (HQ), and l‐cysteine (l‐cys)) for the synthesis of AgNPs. The design was assessed based on the size distribution and zeta potential of the nanoparticles. In addition, the antibacterial activity of the AgNPs against Escherichia coli, Staphylococcus aureus, Serratia marcescens and Salmonella enterica was tested.RESULTSThe results demonstrated that AgNO3 (2 mmol L−1), HQ (20 mmol L−1), l‐cys (20 mmol L−1) and FAD (50.5 nmol L−1) at pH 8.4 were the optimal reaction parameters. The characterization allowed the determination of quasi‐spherical AgNPs with an average hydrodynamic size of 101 nm, a zeta potential of −24 mV and the presence of elemental silver (Ag0) in their composition. Fourier transform infrared spectroscopy showed silver and l‐cys interactions, supporting the role of l‐cys as a coating agent. The antibacterial activity showed that AgNPs displayed a minimum inhibitory concentration of 20–30 μg mL−1 and a minimum bactericidal concentration of 30–40 μg mL−1.CONCLUSIONSThis study demonstrates the feasibility of the reduction of Ag+ to Ag0 using synthetic metabolites, which mimic the reduction and synthesis of fungal biomass. Therefore, it represents a new biocompatible, eco‐friendly and fast method to produce AgNPs. © 2021 Society of Chemical Industry (SCI).