Inducing Salmonella with flhDC increase bacterial tumor colonization and dispersion. a) The microfluidic device contained a media perfusion channel and a chamber that holds tumor cell masses. The perfusion channel mimics tumor vasculature. Masses are formed as spheroids and inserted through tubing and control valves. Prior to insertion, spheroids are approximately 300 μm in diameter. b) Colonization of control Sal (black arrows) and flhDC-induced F-Sal (white arrows) was measured by with red fluorescence (red). Tumor cell masses are shown in the transmitted images under the fluorescence images. Images were background subtracted and shown with the maximum red intensity at the greatest observed value. Scale bar is 100 um. c) Salmonella with induced flhDC (F-Sal) colonized tumors significantly more than Salmonella (Sal) from 29 to 45 hours after bacterial administration (*, P<0.05, n = 3 for Sal and n = 5 for F-Sal). d) F-Sal colonized proximal (x≤0.5) tissue more than control Salmonella (Sal; *, P<0.05). The density was ten-fold greater for F-Sal in distal tumor tissue. e) At 48 hours after administration, F-Sal colonized tumors five-fold more control Sal (*, P<0.05).