A dielectrophoresis method for separating particles from a sample, including a dielectrophoresis channel, the dielectrophoresis channel having a central axis, a bottom, a top, a first side, and a second side
a first mesa projecting into the dielectrophoresis channel from the bottom and extending from the first side across the dielectrophoresis channel to the second side, the first mesa extending at an angle to the central axis of the dielectrophoresis channel
a second mesa projecting into the dielectrophoresis channel from the bottom and extending from the first side across the dielectrophoresis channel to the second side, the second mesa parallel to said first mesa
a space between at least one of the first electrode and the second side or the second electrode and the second side
and a gap between the first electrode and the second electrode, and pumping a recovery fluid through said gap between said first electrode and into said space between at least one of said first mesa and said second side or said second mesa and said second side.