Figure 5
Measured lactate accumulation in hanging drops hosting HCT116 eGFP microtissues. (a) Lactate secretion from one microtissue sample cultured in phosphate-buffered saline (PBS) at 37 °C as measured during an on–off medium perfusion protocol, schematically depicted below the response curves. (b) Experimental arrangement and device set-up, with micrographs of the different HCT116 eGFP microtissue (not to scale) cultured in the different sensing drops in the hanging-drop network. The microtissues were located at the bottom of the hanging drops, at an approximate distance of 1 mm to the electrodes. (c) Lactate secretion of different microtissues cultured in RPMI 1640 cell culture medium at 37 °C during on–off perfusion (schematically depicted below the response curves). Carry-over signal peaks during the washing phase are clearly visible in the two downstream drops. (d) Microtissue-size-dependent lactate secretion rates (black boxes and red dots indicate secretion rates obtained from two consecutive measurements).
