Credit: Danino Lab/Columbia Engineering
FIGURE 3
Copper_Sensing_Strain: The engineered copper sensing strain, grown with samples of water containing high copper (50 mM) which were added as drops onto the left side of the Petri dish. The copper is sensed by the bacteria, which respond by changing their swarming and thus the ring pattern, such that the invisible presence of copper becomes visible to the naked eye. The pattern on the right side of the plate, with no sample, can be used as a baseline to which the left side鈥檚 pattern can be compared.