Unveiling the Antibacterial Mechanism of Gold Nanoparticles by Analyzing Bacterial Metabolism at the Molecular Level

The threat of drug-resistant bacteria is challenging, and it is urgent to explore new antibiotics. Gold nanoparticles (AuNPs) are known to be a group of promising antibacterial agents for replacing conventional antibiotics. Nevertheless, their antibacterial mechanism remains to be elucidated. Herein, we directly observed the interaction between antibacterial AuNPs and bacteria at the molecular level using neutral desorption extractive electrospray ionization mass spectrometry (ND-EESI-MS). We monitored and analyzed the dynamic changes of bacterial metabolites in real time after AuNP treatment. Ten substances representing 3 major metabolic pathways, including protein and nucleic acid synthesis, energy metabolism, and quorum sensing, were identified, indicating that AuNPs may exert antibacterial effects through multiple mechanisms influencing bacterial metabolism and communication. This study deepens the understanding of the antibacterial mechanism of AuNPs and is insightful for designing and screening new antibacterial agents.