Singlet oxygen generation efficiency and antimicrobial ability in glutathione protected Ag31 nanoclusters

Abstract

Ligand protected silver nanoclusters (Ag NCs) have recently been reported to have significant applications as antimicrobial agents. In the current study, glutathione (SG) protected silver nanocluster was synthesized leading to Ag31SG19 by cyclic reduction and oxidative condition and was evaluated for its singlet oxygen generation and antibacterial activity. From the results of the study, Ag31SG19 was found to have inhibitory activity against Escherichia coli and Staphylococcus aureus with a diameter of 15.30 ± 0.58 mm and 16.70 ± 0.58 mm respectively. The Minimum Inhibitory Concentration was also calculated to have 0.3125 mg/ml and 0.1562 mg/ml respectively. In addition, the Ag31SG19 was found to have high efficiency for the generation of singlet oxygen. Based on the results of the study, the antimicrobial mechanisms of Ag31SG19 could be predicted to be mainly because of the generation of singlet oxygen species in addition to the activity due to the release of Ag+ ions from the nanoclusters. These multimechanistic antimicrobial effects make the synthesized Ag31SG19 to be a promising candidate for a broad range of antimicrobial applications.