We overview the ways in which electric fields can be used for on-chip manipulation and assembly of colloidal particles. Particles suspended in water readily respond to alternating (AC) or direct current (DC) electric fields. Charged particles in DC fields are moved towards oppositely charged electrodes by electrophoresis. Dielectrophoresis, particle mobility in AC fields, allows precise manipul...

We present experimental results and modeling on the efficacy of dielectrophoresis-based single-particle traps. Dielectrophoretic forces, caused by the interaction of nonuniform electric fields with objects, have been used to make planar quadrupole traps that can trap single beads. A simple experimental protocol was then used to measure how well the traps could hold beads against destabilizing f...

The scanning dielectrophoresis system consists of a pair of microneedles connected to a waveform generator of arbitrary ac electric fields. Consequently, our scanning method is able to place and move the strong electric field spot between the electrode tips anywhere, just as optical tweezers have done the focus of light beam. In this paper, we demonstrate non-contact manipulations unique to our...

We present the site-selective, parallel and reproducible formation of conductive gold and tetrathiafulvalene-gold (TTF-Au) hybrid micro- and nanowires from their respective ion salt and cation-radical solutions. While the formation of micro- and nanowires by means of dielectrophoresis with directly coupled electrodes has been thoroughly investigated in recent studies, we present here the first ...

Analysis of the movement of particles in a nonuniform field requires accurate knowledge of the electric field distribution in the system. This paper describes a method for analytically solving the electric field distribution above interdigitated electrode arrays used for dielectrophoresis (DEP) and traveling wave dielectrophoresis (twDEP), using the Schwarz-Christoffel mapping method. The elect...

Dielectrophoresis (DEP) uses non-uniform electric fields to cause motion in particles due to the particles' intrinsic properties. As such, DEP is a well-suited label-free means for cell sorting. Of the various methods of implementing DEP, contactless dielectrophoresis (cDEP) is advantageous as it avoids common problems associated with DEP, such as electrode fouling and electrolysis. Unfortunate...

We present a theoretical study of dielectrophoretic (DEP) crossover spectrum of two polarizable particles under the action of a nonuniform ac electric field. For two approaching particles, the mutual polarization interaction yields a change in their respective dipole moments, and hence, in the DEP crossover spectrum. The induced polarization effects are captured by the multiple image method. Us...

Magnetic force microscope ( MFM ) is a powerful technique for mapping the magnetic force gradient above the sample surface. Herein, single-wall carbon nanotubes (SWCNT) were used to fabricate MFM probe by dielectrophoresis method which is a reproducible and cost-effective technique. The effect of induced voltage on the deposition manner of carbon nanotubes (CNT) on the atomic force microscope (...

In this paper, we will propose a dielectrophoresis-based microchannel system. Based on numerical calculations and theoretical analysis, we investigate the dynamic behaviors of a microparticle in this system, in the presence of nonuniform electric fields generated by point microelectrodes. Good agreement is shown between them. It is found that the microelectrodes enable the system equilibrium to...

Polarizable liquids respond to a non-uniform electric "eld by collecting preferentially in regions of maximum "eld intensity. This manifestation of dielectrophoresis (DEP) is a wellknown example of the ponderomotive force, with the "eld acting on individual (molecular) dipoles in the liquid. When electrode dimensions are scaled down to &10 to 100 m, liquid DEP makes possible a new type of high-...