Fig. 4: Calibration of the low-voltage sorter.
From: Droplet digital microfluidic system for screening filamentous fungi based on enzymatic activity
a Gating histogram. Peak intensities of the 5 µM (shown in blue) and 50 µM (shown in red) fluorescein-containing droplets were measured when passing through the microfluidic sorter using a peak detection algorithm (N = 500). b Experimental overview. A mixed droplet library was reinjected into the sorter, of which the sorting gate was set to fit the 5 µM fluorescein histogram, and autonomous sorting with total oil flow of 0.03 µL/s, PE 10 kHz, 15 VRMS, 0.3 s, and droplet travel time of 0.1 s. c Droplet populations from each outlet after autonomous sorting of a mixed population of 5 µM fluorescein positive (P) droplets and negative (N) blue dye droplets. Sorted positive droplets are expected to flow into the disfavored channel, with the negative droplets flowing into the main channel. From observation of the bright-field and 480 nm-excited fluorescence microscopy images of the droplets recovered from both sorting outlets, the sensitivity (77.14%) and specificity (99.52%) of the sorter were calculated.
