The Lysis Mechanisms of Bacterial Cell Wall by the Ag Quantum Dots Synergistic Zn Cu-Based Ferrites

Abstract

Ultrasmall particle-sized Ag nanoparticles (UANs) have attracted significant attention because of their strong antibacterial activity against pathogenic and drug-resistant bacteria. However, the preparation method, antibacterial mechanism, and toxicity reduction of UANs to human cells need to be improved for practical applications of UANs based on a variety of biological antibacterial activities. In this study, 1.75 nm Ag quantum dots were anchored on the surface of ZnFe2O4@Cu2S derived from the topology ZIF-8 and the adsorption and reduction processes. The 99.99% of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and methicillin-resistant Salmonella (T-Salm) at a concentration of 175 μg/mL was inhibited within 15 min. The trapping experiments of reactive oxidative species revealed that the bacteriostatic activity was boosted by a large amount of •OH generated over ZnFe2O4@Cu2S@Ag (FCA). Combining the experimental and theoretical analyses, bacterial death was induced by destroying the ion channel protein in the bacterial cell wall over FCA, leaking the electrolytes in the bacterial cell. Additionally, the toxicity of Ag nanoparticles can be reduced by incorporating highly biocompatible Zn, Fe, Cu, and S elements. The crucial strategies might provide new insights into the rational design and application of medical dressing for UANs.

Keywords: nanocomposites, Ag nanoparticles, Antibacterial materials, Bacteriostatic activity, Antibacterial mechanism