Biogenic fabrication of silver nanoparticles, oxidative dissolution and antimicrobial activities

Abstract

Metallic silver nanoparticles (AgNPs) were prepared by using Foeniculum vulgare Mill seeds extract. The silver nitrate was used as silver precursor in an aqueous solution. The photooxidative dissolution of AgNPs with persulfate (K2S2O8) under UV light was investigated. Effects of initial concentration of K2S2O8, AgNPs, initial solution pH, and temperature were studied on dissolution of AgNPs. The 100% AgNPs dissolution was achieved in 60 min under typical conditions (pH = 4.0, 1.2 mM K2S2O8, and 30 0C). The experimental results showed higher temperature brought faster dissolution rate, and the activation energy was 65.2 kJ/mol. The effects of ethanol, tertiary butanol, and nitrobenzene were studied to establish the role of SO4−· and HO· radical species. AgNPs dissolution was inhibited by Cl−, Br−, I−, and NO3− ions. Staphylococcus auerus (s. aureus), Escherichia coli (E. coli) and Candida albicans (C. albicans) were the effective human pathogens against the AgNPs. The lag phase, growth kinetics, minimum bactericidal concentration, death rate, and antimicrobial efficacy depend on the concentration of AgNPs.

Keywords

• Fennel seeds
• AgNPs
• Oxidative dissolution
• Antimicrobial