Fig. 3: Evaluating the sorting efficiency at different flow rates and under different electric potential conditions.
From: Droplet digital microfluidic system for screening filamentous fungi based on enzymatic activity
a A heatmap showing the efficiency of electrostatic droplet sorting (%) at different oil flow rates (nL·s−1) and applied potentials (VRMS). The success rate of sorting was determined by counting the number of droplets that successfully entered the disfavored channel (true, T) and those that entered the main channel (false, F). The highest sorting success is displayed as a blue area, and the lowest success is shown as the pink area. The optimal flow rate and potential to achieve 100% success are >51.5 nL·s−1, 27.4 VRMS. The lowest potential at which we observed perfect sorting (100%, N = 10) was at 12.5 VRMS, 50 nL s−1. This graph was created by polynomial fitting using a binomial regression with an interaction term, AIC: 1029.1 with coefficients P < 0.05, N = 10 per condition. Three failed sorting conditions were observed and labeled E1, E2, and E3. b Time-course snapshots of three failed sorting conditions. Actuated electrodes are indicated with a white dot, and the droplet is outlined in red. E1: Droplets immediately enter the main channel (low potential, high flow rate). E2: Droplets enter the disfavored channel, but switch to the main channel after the PE pulse (low flow rate; high potential). E2 and E3: Droplets can merge with the next arriving droplet (low flow rate)
