(A-B) Plots of intracellular NPs in the cells: (a) WT, (b) nalB1 and (c) ΔABM, versus time, for the cells incubated with (A) 770 pM of 13.1 ± 2.5 nm NPs and (B) 3.7 pM of 91.0 ± 9.3 nm NPs for 2 h, show that accumulation of intracellular NPs depends upon the expression levels of MexAB-OprM and sizes of NPs.
(C) Plots of intracellular NPs versus time, for the cells (nalB1) that are incubated with 3.7 pM of 91.0 nm Ag NPs (a) in the presence and (b) absence of CCCP, show that the number of intracellular NPs is nearly doubled in the presence of CCCP.
(D) Time-courses of fluorescence intensity of intracellular EtBr for the cells: (a) WT, (b) nalB1 and (c) ΔABM cells, incubated with 4 µM EtBr for 2 h, show that accumulation of intracellular EtBr depends upon the expression levels of MexAB-OprM.