Figure 2.

Effect of silver nanoparticles (AgNPs) on the single bacterial cell. (A) AgNPs penetrate through the cell membrane and cause its disruption; intracellular metabolites are released via the disrupted membrane. (B) AgNPs release silver ions (Ag⁺) to generate reactive oxygen species (ROS) and induce oxidative stress. (C) ROS are, for example, responsible for lipid peroxidation, which significantly changes the distribution of intracellular and extracellular metabolites and causes a change in membrane permeability, because lipid strains are repulsed. Interaction of AgNPs and Ag⁺ with proteins can affect (D) DNA enzymatic replication machinery, (E) DNA transcription, (F) translation of DNA to polypeptide/protein chain on ribosomes (red-brown ovals), (G) proton efflux pumps, (H) electron transport chain (represented by blue, yellow and green ovals) and creation of energetic sources of cells (ATP). Adapted from [31], Copyright Springer Nature, 2013.