Methods and systems employing electrothermally induced flow for mixing and cleaning in microsystems

Abstract

A method and system for controlling flow motion in a channel/cavity in a microfluidic system includes positioning at least one pair of electrodes in and/or proximate to the channel/cavity. A buffer solution is placed in the channel/cavity, the buffer solution having at least one dielectric property that varies in response to changes in temperature of the solution. An AC/DC voltage is applied to the electrodes to generate an electric field in the channel/cavity; the AC voltage having a known magnitude and frequency and the DC voltage having a known magnitude. The magnitude of the AC/DC voltage is adjusted to cause Joule heating of the buffer solution in the channel/cavity. The geometry and position of the electrodes is adjusted to generate a temperature gradient in the buffer solution, thereby causing a non-uniform distribution of the dielectric property within the solution in the channel/cavity. The dielectric non-uniformity produces a body force and flow in the solution. Also, the frequency of the AC voltage is adjusted to generate flow of the buffer solution in the channel/cavity in response to the non-uniform distribution of the dielectric property.