Graduate Research and Discovery Symposium (GRADS)


Saurin H. Patel


Dr. Xiangchun Xuan

Document Type



Mechanical Engineering

Publication Date

Spring 2013


Dielectrophoresis (DEP) is the translation of a particle either along (i.e., positive dielectrophoresis) or against (i.e., negative dielectrophoresis) an electric field gradient if the particle is more or less polarizable than the suspending medium. The polarizability of a particle is dependent on its electrical and mechanical properties. This makes DEP a versatile tool for particle and cell handling, especially in microdevices due to its favorable scaling. Traditional DEP is realized through patterning pair(s) of microelectrodes onto the surface of a micro channel. Recently DEP has also been implemented by the use of channel geometry, which can be the variation in channel cross-section or the curvature of the channel itself. Both methods, however, rely on in-channel electrical or mechanical parts to create electric field gradients, which complicate device fabrication and causes fouling trouble due to electrochemical reactions and electrothermal flow effects etc. Reservoir-based dielectrophoresis (rDEP) is a newly developed microfluidic method that exploits negative dielectrophoresis induced at the reservoir-microchannel junction to manipulate particles inside a reservoir. As the rDEP focusing, concentration and separation of particles all take place inside a reservoir; the entire microchannel can be spared for pre- and post-analysis. This makes the rDEP method perfectly positioned for lab-on-a-chip applications.