A low cost solution for the fabrication of dielectrophoretic microfluidic devices and embedded electrodes.

The versatility of a simple method for producing microfluidic devices with embedded electrodes is demonstrated through the fabrication and operation of two dielectrophoretic devices; one employing interdigitated electrode structures on glass and the other employing contactless electrode reservoirs. Device manufacture is based on the precipitation of silver and subsequent photolithography of thin film resists conducted outside of a cleanroom environment. In current experiments, minimum channel widths of 50 microns and electrode widths of 25 microns are achieved when the distance between features is 40 microns or greater.

High-frequency irreversible electroporation (H-FIRE) for non-thermal ablation without muscle contraction.

Background: Therapeutic irreversible electroporation (IRE) is an emerging technology for the non-thermal ablation of tumors. The technique involves delivering a series of unipolar electric pulses to permanently destabilize the plasma membrane of cancer cells through an increase in transmembrane potential, which leads to the development of a tissue lesion. Clinically, IRE requires the administration of paralytic agents to prevent muscle contractions during treatment that are associated with the delivery of electric pulses.

Modeling and development of a low frequency contactless dielectrophoresis (cDEP) platform to sort cancer cells from dilute whole blood samples.

Contactless dielectrophoresis (cDEP) devices are a new adaptation of dielectrophoresis in which fluid electrodes, isolated from the main microfluidic channel by a thin membrane, provide the electric field gradients necessary to manipulate cells. This work presents a continuous sorting device which is the first cDEP design capable of exploiting the Clausius-Mossotti factor at frequencies where it is both positive and negative for mammalian cells. Experimental devices are fabricated using a cost effective technique which can achieve 50 μm feature sizes and does not require the use of a cleanroom or specialized equipment.

Selective isolation of live/dead cells using contactless dielectrophoresis (cDEP).

Contactless dielectrophoresis (cDEP) is a recently developed method of cell manipulation in which the electrodes are physically isolated from the sample. Here we present two microfluidic devices capable of selectively isolating live human leukemia cells from dead cells utilizing their electrical signatures. The effect of different voltages and frequencies on the gradient of the electric field and device performance was investigated numerically and validated experimentally.

Contactless dielectrophoresis: a new technique for cell manipulation.

Dielectrophoresis (DEP) has become a promising technique to separate and identify cells and microparticles suspended in a medium based on their size or electrical properties. Presented herein is a new technique to provide the non-uniform electric field required for DEP that does not require electrodes to contact the sample fluid. In our method, electrodes are capacitively-coupled to a fluidic channel through dielectric barriers; the application of a high-frequency electric field to these electrodes then induces an electric field in the channel.