Laser-induced confocal microscope and microfluidic device for dielectrophoretic fluorescence-activated droplet sorting

A system for sorting droplets comprising:

• a microfluidic chip comprising a droplet sorting channel coupled at an upstream location to a droplet inlet channel, the droplet sorting channel coupled at a downstream location to a sorting junction which leads to a waste channel and a collection channel;
• an optical interrogation device configured to illuminate each droplet as it passes through the sorting channel with excitation light from an excitation light source, detect emitted fluorescent light from each droplet, and generate a respective output signal corresponding to the fluorescence of each respective droplet;
• a diverter disposed in the microfluidic chip upstream of the sorting channel and configured to be actuated to selectively direct each droplet into one of the collection channel or the waste channel, the diverter operably coupled to a controller which controls the actuation of the diverter;
• wherein the controller is configured to receive the output signal for each droplet from the optical interrogation device, and control the actuation of the diverter based on the output signal for each droplet to selectively direct each droplet into one of the collection channel or the waste channel;
• and
• wherein the microfluidic chip further comprises an elevated divider interposed between the waste channel and the collection channel at the sorting junction and extending downstream of the sorting junction for a divider length, wherein the elevated divider separates only an upper portion of the waste channel and the collection channel for the divider length and leaves a lower portion of the waste channel and the collection channel fluidly connected by a dead-end channel below the elevated divider and wherein downstream of the elevated divider and the dead-end channel, a border wall completely separates the waste channel and the collection channel.