Figure 4. Optical sensing modalities tested for droplet sorting based on DNA modifying enzymes.

Droplet based detection of four different classes of nucleic acid modifying enzymes were performed using recombinant enzymes that catalyze (a) polymerase extension, (b) strand displacement, (c) restriction enzyme digestion, and (d) DNA ligation activities. Data is presented as the distribution of peak droplet fluorescence for each population. The peak value fluorescence describes the maximum fluorescence reading of a droplet as it passes in front of the laser line. The max standard is a chemically synthesized version of the product obtained from the enzymatic reaction.