Silver nanoparticles (SNPs) exhibit strong antibacterial activity against Escherichia coli. This study investigated the antibacterial activity and mechanism of SNPs on E. coli ATCC 8739 by analyzing bacterial growth, permeability, and morphology after treatment with SNPs. The results showed that 10 μg/ml SNPs could completely inhibit the growth of 10⁷ cfu/ml E. coli cells in liquid Mueller-Hinton medium. SNPs caused leakage of reducing sugars and proteins and inactivated respiratory chain dehydrogenases, indicating damage to bacterial membranes. Transmission and scanning electron microscopy revealed severe damage to E. coli cells exposed to 50 μg/ml SNPs, including membrane fragmentation and the dissolution of membrane vesicles. These findings suggest that SNPs damage bacterial cell membranes and inhibit membranous enzyme activity, leading to cell death. Silver has long been known for its antimicrobial properties, but its use in nanoscale form has recently gained attention. SNPs have been shown to have effective antimicrobial activity and are used in various healthcare products. The mechanism of silver toxicity involves disrupting the proton motive force, inhibiting DNA activity, and inactivating enzymes. SNPs may target bacterial membranes, leading to the dissipation of the proton motive force and cell death. This study provides evidence that SNPs can inhibit bacterial growth and kill cells by damaging bacterial membrane structure and permeability. The results suggest that SNPs may be effective antimicrobial agents due to their ability to disrupt bacterial membranes and inhibit essential cellular processes.Silver nanoparticles (SNPs) exhibit strong antibacterial activity against Escherichia coli. This study investigated the antibacterial activity and mechanism of SNPs on E. coli ATCC 8739 by analyzing bacterial growth, permeability, and morphology after treatment with SNPs. The results showed that 10 μg/ml SNPs could completely inhibit the growth of 10⁷ cfu/ml E. coli cells in liquid Mueller-Hinton medium. SNPs caused leakage of reducing sugars and proteins and inactivated respiratory chain dehydrogenases, indicating damage to bacterial membranes. Transmission and scanning electron microscopy revealed severe damage to E. coli cells exposed to 50 μg/ml SNPs, including membrane fragmentation and the dissolution of membrane vesicles. These findings suggest that SNPs damage bacterial cell membranes and inhibit membranous enzyme activity, leading to cell death. Silver has long been known for its antimicrobial properties, but its use in nanoscale form has recently gained attention. SNPs have been shown to have effective antimicrobial activity and are used in various healthcare products. The mechanism of silver toxicity involves disrupting the proton motive force, inhibiting DNA activity, and inactivating enzymes. SNPs may target bacterial membranes, leading to the dissipation of the proton motive force and cell death. This study provides evidence that SNPs can inhibit bacterial growth and kill cells by damaging bacterial membrane structure and permeability. The results suggest that SNPs may be effective antimicrobial agents due to their ability to disrupt bacterial membranes and inhibit essential cellular processes.