Fig. 1

Comparison of cell viabilities of G⁺ and G⁻ bacteria exposed to ENMs. a Heat maps displaying the toxicity of ENMs in E. coli and B. subtilis cells. E. coli and B. subtilis suspensions were exposed to different nanoparticles for 2 h. Then the cell viabilities were determined by bacteria counting colorimetric assay. Three replicates were conducted for each dosage. b Survival rate examination by CFU assay. The colonies of E. coli, P. aeruginosa, S. aureus and B. subtilis were counted after exposure to La₂O₃ at 250 μg/mL. Columns and error bars represent the mean and the standard deviation of three replicates. ***p < 0.001 compared to G⁻ cells by two-tailed Student’s t-test. c Live/Dead staining. E. coli and B. subtilis cells were incubated with La₂O₃ and stained by a Live/Dead staining kit for confocal microscopy imaging. Scale bar is 7 μm