Unveiling the Antibacterial Mechanism of Gold Nanoclusters via In Situ Transmission Electron Microscopy

Jui Chi Kuo, Shih Hua Tan, Yu Cheng Hsiao, Chinmaya Mutalik, Hui Min Chen, Sibidou Yougbaré, Tsung Rong Kuo

Research output: Contribution to journalArticlepeer-review

Abstract

Metal nanoclusters (NCs) with unique chemical and physical properties have been extensively demonstrated to be emerging nanoantibiotics for fighting bacterial infections. Understanding the antibacterial mechanisms of metal nanoclusters is important for evaluating their clinical applications as nanoantibiotics. To understand the antibacterial mechanism, gold nanoclusters (AuNCs) were applied as an antibacterial agent for real-time observations of their interactions with bacteria by in situ transmission electron microscopy (TEM). In this work, a surface ligand of glutathione-conjugated (GSH)-AuNCs was prepared via a simple hydrothermal method. Optical and structural characterizations validated the successful preparation of GSH-AuNCs. Bacterial growth curves of Acetobacter aceti revealed that the antibacterial activity of GSH-AuNCs increased with the weight concentration. The antibacterial activity of GSH-AuNCs was confirmed by the intracellular reactive oxygen species (ROS) generation induced by GSH-AuNCs in A. aceti. Furthermore, real-time observations of interactions between GSH-AuNCs and A. aceti were made using in situ liquid cell TEM. Based on the results of real-time observations, GSH-AuNCs first attached onto the bacterial membranes of A. aceti by physical adsorption and then penetrated into A. aceti by internalization. Eventually, the production of intracellular ROS induced by GSH-AuNCs caused destruction of the bacterial membranes, which led to the death of A. aceti. After the bacterial membranes had been destroyed, A. aceti eventually died.

Original languageEnglish
Pages (from-to)464-471
Number of pages8
JournalACS Sustainable Chemistry and Engineering
Volume10
Issue number1
DOIs
Publication statusPublished - Jan 10 2022

Keywords

  • antibacterial mechanism
  • in situ TEM
  • nanocluster
  • reactive oxygen species
  • real-time observation

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Renewable Energy, Sustainability and the Environment

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