Fig. 3.

In vitro co-culture. (a) Schematic of the microfluidic co-culture with cancer cells and bacteria. Fluidic resistance was modified in this chip to achieve stable near-stagnant flow reduction to allow for cancer cell adherence and for diffusion of released therapeutic from the trap to the channel (methods in Supplementary Information). (b) Frames from the co-culture time series sequentially visualizing S. typhimurium (Strain 3) ‘firing’, lysis, and HeLa cell death. (c) Fluorescent profile of the bacteria and HeLa cell viability fraction (# live cells / # dead cells in image frames) from (b) with time. (d) % viability of HeLa cells co-cultured with supernatant from S. typhimurium culture harboring the SLC + HlyE (Strain 4), the SLC only (Strain 5), constitutive hlyE only (Strain 6), or no plasmid (Strain 7). Error bars indicate ±1 standard error averaged over three measurements. (e) Fluorescence profile of the SLC + HlyE (Strain 4) co-cultured with HeLa cells at various initial seeding densities. The black ‘x’ marks the point of complete HeLa cell death. (f) The toxin exposure time, measured from the initial presence of fluorescence to HeLa cell death, as a function of the sfGFP production rate (see example in (e)). Although the time to death depends on seeding, the total magnitude of exposure remains conserved (inset). Error bars indicate ±1 standard error for three measurements. See Supplementary Information for ELH1301 host strain information.