Patent ID: 8608929

Claim:
A method for concentrating target particles, the method comprising: providing a liquid sample comprising particles, including the target particles, in a reservoir and introducing the target particles from the reservoir into a thin layer of a medium with which the target particles can reversibly bind by applying a first electric field across a boundary between the reservoir and the medium; applying a sequence of second electric fields to the medium by applying electrical potentials to three or more non-collinear electrodes spaced apart around a periphery of the medium, the sequence of second electric fields causing the target particles in the medium to converge toward a focus location, wherein at least some of the second electric fields vary spatially in the medium such that, in a first area of the medium on a line between a first one of the electrodes and the focus location, the second electric field is oriented in a vector direction to urge the target particles toward the focus location and a magnitude of the second electric field in the first area of the medium is greater than a magnitude of the second electric field in a second area of the medium on a line between a second one of the electrodes and the focus location wherein: the first and second areas are equidistant from the focus location; and in the second area the second electric field has a vector direction non-parallel to a vector direction of the second electric field in the first area such that target particles in the second area are urged away from the focus location by the second electric field in the second area.