Patent ID: 6942776

Claim:
An apparatus for manipulating particles immersed in a fluid by dielectrophoresis, comprising: a) a first substrate; b) a group of electrodes comprising a first electrode array comprising a plurality of electrodes having spaces there between formed on the first substrate and a second electrode array comprising at least one electrode, the second electrode array facing and being spaced apart from the first electrode array, the particles and the fluid being placed in a region between the first electrode array and the second electrode array; and c) means for establishing a non-uniform electric field, having constant magnitude over at least one imaginary closed surface located entirely in the fluid, and where the means for establishing a non-uniform electrical field comprises means for applying a first periodic signal having a frequency and a first phase to a first subset of the plurality of electrodes in the first electrode array and at least one other periodic signal having the frequency and a second phase, opposite to the first phase, to at least one other subset of the plurality of electrodes in the first electrode array; and where the electrode of the second array faces the plurality of electrodes of the first electrode array, and is formed on a second substrate opposed to the first substrate.