System for generating droplets with pressure monitoring

A method of generating droplets, the method comprising:

• selecting a device including a plurality of separate emulsion-formation units each including a sample well, a continuous-phase well, a droplet well, and a channel network that fluidically interconnects the wells and creates a droplet-generation region;
• placing a discrete volume of sample-containing fluid into the sample well of each emulsion-formation unit, and a discrete volume of continuous-phase fluid into the continuous-phase well of each emulsion-formation unit;
• applying negative pressure to the droplet well of each of the emulsion-formation units via a manifold after the step of placing, with the manifold sealed to each droplet well via a same gasket, such that in each emulsion-formation unit (a) sample-containing fluid flows from the sample well to the droplet-generation region, (b) continuous-phase fluid flows from the continuous-phase well to the droplet-generation region, and (c) sample-containing droplets and continuous-phase fluid flow from the droplet-generation region to the droplet well, wherein the plurality of emulsion-formation units generate droplets in parallel with one another;
• detecting a pressure signal corresponding to the negative pressure;
• and
• stopping application of negative pressure to all of the droplet wells in parallel when the pressure signal indicates that air has entered the channel network of an emulsion-formation unit.