Patent ID: 7816121

Claim:
A droplet actuation system comprising: (a) a droplet actuation device comprising: (i) a substrate comprising electrodes for conducting droplet operations; and (ii) one or more temperature control means arranged in proximity with one or more of the electrodes for heating and/or cooling a region of the droplet actuation device and arranged such that a droplet can be transported on the substrate by the electrodes into the region for heating; and (iii) a means for effecting a magnetic field in proximity to one or more of the electrodes, wherein the strength and proximity of the magnetic field is sufficient to immobilize magnetically responsive beads in a droplet on the substrate during execution of a droplet operation; and (b) a processor electronically coupled to and configured to control the electrodes and the temperature of one or more of the one or more temperature control means, wherein the processor is programmed, and the electrodes and magnetic field are arranged, to cause the electrodes to split a droplet comprising the magnetically responsive beads yielding a first daughter droplet which comprises the magnetically responsive beads and a second daughter droplet without a substantial amount of the magnetically responsive beads.