Figure 5.

Detection of fluorescent signals from positive and negative droplets. A positive droplet contains more than one target DNA copy, allowing for the detection of a fluorescent signal after DNA replication. By contrast, a negative droplet lacks the target DNA, and any small signal detected arises from the background fluorescence of the EVA Green dye in the droplets. It is essential to set an appropriate threshold voltage to accurately differentiate between positive and negative droplets. The orange line represents the highest threshold, set at twice the average intensity of the no-template control (NTC) droplet fluorescence signals. The blue line represents the lowest threshold, determined by 10 times the standard deviation (S.D.) of the fluorinated oil signal.