Construction and characterization of environment-friendly antibacterial Mg(OH)2 nanoparticles and their induced metabolic changes in Escherichia coli†

In recent years, microbial pollution has become a serious environmental problem, and the release of microorganisms into the water environment seriously threatens human health. As environment-friendly and low-cost antibacterial agents, Mg(OH)₂ nanoparticles (M-NPs) have garnered considerable attention for their small size, innocuity, no drug resistance, chemical stability and thermal stability. However, little is known about the physiological changes that bacteria undergo in the presence of M-NPs. In this work, the antibacterial mechanism of M-NPs synthesized by applying the coprecipitation method was investigated using Escherichia coli (E. coli) as a model system. The oxygen vacancies on the M-NP surface, which can produce reactive oxygen species (ROS, ·O₂⁻, H₂O₂, and ·OH), were examined via O₂-temperature programmed desorption (O₂-TPD). Abnormality in three central metabolic pathways (energy, glucose and tricarboxylic acid cycle) induced by M-NPs was detected by analyzing the activity of respiratory chain dehydrogenase, gluconokinase (GK) and succinate dehydrogenase (SDH). The downregulated activity and gene expression levels of GK confirmed that M-NPs play an inhibitory role, and these physiological changes result in cell death. Thus, M-NPs have great potential in the field of preventing and controlling microbial pollution.