Patent ID: 7815871

Claim:
A droplet microactuator system comprising: (a) a cartridge comprising: (i) a droplet microactuator comprising a substrate comprising electrodes configured to conduct droplet operations in a gap formed by the substrate of the droplet microactuator and a second substrate; (ii) a cartridge reservoir and a fluid path from the cartridge reservoir into the gap; (iii) a mechanical mechanism, electrical mechanism, pressure source and/or vacuum source for forcing fluid through the fluid path; and (iv) a droplet in the gap comprising magnetically responsive beads; (b) a magnetic field source arranged to immobilize the magnetically responsive beads in the droplet in the gap during a droplet operation mediated by the electrodes; (c) an optical sensor configured in a sensing relationship with the droplet microactuator, such that the sensor is capable of sensing an optical signal from and/or an optical property of one or more droplets on the droplet microactuator; and (d) one or more processors electronically coupled to the droplet microactuator and programmed to: (i) control the droplet operations on the droplet microactuator, wherein the droplet operations conduct one or more droplet-based assay protocols using droplet operations comprising one or more electrowetting-mediated droplet operations and the droplet-based assay protocols comprise one or more electrowetting-mediated bead-washing protocols; and (ii) process electronic signals from the optical sensor.