Patent ID: 8277628

Claim:
A device for carrying out biological assays, having at least one fluid channel, a reaction area with an opening exposed to the fluid channel, and a bottom of the reaction area offset from the fluid channel, the device being constructed for fluid flow in a direction transverse to a reaction area opening, comprising: (a) a first electrode adjacent to the bottom of the reaction area; (b) a second electrode adjacent to the reaction area opening; and (c) a controllable voltage source connected to the first and second electrodes which is controllable to provide an alternating voltage with a superimposed DC bias voltage between the first electrode and the second electrode to create an electric field between the first electrode and the second electrode, the first electrode and the second electrode being capacitively coupled so that charged species in a fluid in the fluid channel are directed into or out of the reaction area by the electric field between the electrodes produced by the controllable voltage source.