4.2.5 Flow cytometry.
The uptake efficiency of Td in bacteria was estimated by flow cytometry. The transfected samples were centrifuged at 6000 g/min for 5 min and washed twice with PBS. After resuspending in PBS, the samples were detected with a blue laser (488 nm excitation) and a 530/30 filter in the BL1 detector by a NovoCyteTM flow cytometer.