Figure 5.

Representative images of TFM recording during infection

(A) Columns show representative phase contrast images of host MDCK cells in monolayer, L.m. fluorescence and fluorescence of the tracer beads embedded on the upper surface of a 3 kPa polyacrylamide hydrogel on which host MDCK cells reside. Rows show representative two time points at early (4 hpi) and late (24 hpi) infection. Note that brightness has been enhanced for the upper image (4 hpi) so that the bacterial fluorescence signal is visible.

(B) Reference image of the tracer beads for the representative recording shown in panel A (top-left) and examples of bad tracer beads’ distribution because: of the beads’ layer being too thick (top-right); of cracks on the upper hydrogel layer (bottom-left); or of the hydrogel not being flat so the beads in the bottom area in the field of view are out of focus (bottom-right).