Patent ID: 8637324

Claim:
A method of manipulating a droplet having magnetically responsive beads therein, the method comprising: (a) providing a droplet actuator comprising: (i) droplet operations electrodes arranged for conducting droplet operations on a droplet operations surface; and (ii) a magnet positioned relative to the droplet operations surface such that a droplet controlled by one or more of the droplet operations electrodes may be positioned within or away from a region of the magnet's magnetic field capable of substantially attracting magnetically responsive beads in the droplet; (b) positioning a droplet having magnetically responsive beads therein at a location on the droplet operations surface within the region of the magnetic field to form a concentration of beads in the droplet; and (c) removing the droplet from the region of the magnetic field by transporting the droplet through activation of selected droplet operations electrodes away from the region of the magnetic field without removing the magnet, thereby resuspending the magnetically responsive beads in the droplet.