Figure 6.

Sorting of viable/non-viable E. coli using electrokinetic DLD (eDLD). (a) Lateral displacement of the viable and non-viable E. coli based on fluorescence intensity at the beginning and at end of a DLD array (Sorting device #1, D_C = 1.24 µm), with and without an applied field. The displacement corresponding to the zigzag/intermediate/displacing reservoirs have been marked with the orange/gray/green horizontal bars, respectively. Note that there seems to be some separation of non-viable cells from viable cells even when the electric field is switched off, probably due to the higher probability of non-viable cells to form aggregates. While roughly half of the non-viable cells can be collected, the remainder is still mixed with viable cells. For the general case, this level of sorting is of limited value. (b) External, manual counts of the ratio between viable and non-viable E. coli recovered from different outlet reservoirs. “Hybrid” refers to the few cells emitting both green and orange color, which represents a minute subset of the counted cells.