Fig. 4: Interaction of AgNCs and AgNPs with bacterial cells.

a Representative TEM images showing the interaction of AgNCs and AgNPs with P. aeruginosa cells after 6 h of exposure. Blue arrowheads indicate agglomerated particles outside cells, red arrowheads denote AgNCs inside cells, and orange arrows point at cell debris. The enlarged images show the detailed interplay between AgNCs, AgNPs, and bacteria. b Evaluation of cell wall/membrane damage using PI staining (in red) in MDR P. aeruginosa cells upon AgNPs and AgNCs at 6.4 μg/mL for 6 h. Images were visualized through confocal microscopy (×600, original magnification). c Quantitative data of PI-positive cells (n = 3). d Relative extracellular MDA levels in culture media from P. aeruginosa MDR cells treated with AgNPs and AgNCs at 6.4 μg/mL for 6 h (n = 3). The level in the untreated control was normalized to 1.0. A pound sign (#) denotes P < 0.05 for AgNCs compared to AgNPs. e and f Cellular uptake of AgNPs and AgNCs, as reflected by Ag mass, in P. aeruginosa cells after treatment for 6 h (n = 3). The e panel indicates the total silver mass, and the f panel denotes the silver in association with the plasma membrane. g Calculation of the ratio between the mass on the membrane and the total amount for AgNCs and AgNPs, respectively (n = 3).