Particle movement in microelectrode structures in AC electric fields, under the influence of dielectrophoresis and electrohydrodynamics
Nicolas G Green
University of Glasgow, UK
Keywords: dielectrophoresis, electrohydrodynamics, electroosmosis, particle
The use of AC electric fields for the manipulation, characterisation and separation of particles in suspension (dielectrophoresis: DEP) has become an area of considerable interest, both in basic research of the underlying physical mechanisms  and commercial application [2,3]. Dielectrophoresis has been developed into a technique for the development of Micro Total Analysis Systems (see for example ) particularly for particle or cell sorting in microsystems. It is likely that there will be considerable future development of this technique in the area of microsystems and the Lab-on-a-chip, which is currently a major area of research and industrial effort.
This paper presents simulations of the motion of particles under the influence of dielectrophoresis , electrothermal fluid flow  and AC electroosmosis . This work is the first attempt to produce an accurate model, combining these three effects, for the behaviour of micrometre and sub-micrometre scale particle in AC electric fields on microelectrodes. The results of the simulations are compared with experimental measurements and observations of fluorescent particles suspended in aqueous electrolytes on microelectrodes. The strong influence of the fluid flow on particle behaviour is conclusively demonstrated as well as the potential of using controlled fluid flow for the practical purpose of particle separation.
NSTI Nanotech 2003 Conference Technical Program Abstract