Particle Manipulation in Insulator Based Dielectrophoretic Devices1

Abstract

Microfluidic devices can make a significant impact in many fields where obtaining a rapid response is critical, particularly in analyses involving biological particles, from deoxyribonucleic acid (DNA) and proteins, to cells. Microfluidics has revolutionized the manner in which many different assessments/processes are carried out, since it offers attractive advantages over traditional bench-scale techniques. Some of the advantages are: small sample and reagent amounts, higher resolution and sensitivity, improved level of integration and automation, lower cost and much shorter processing times. There is a growing interest on the development of techniques that can be used in microfluidics devices. Among these, electrokinetic techniques have shown great potential due to their flexibility. Dielectrophoresis (DEP) is an electrokinetic mechanism that refers to the interaction of a dielectric particle with a spatially non-uniform electric field; this leads to particle movement due to polarization effects. DEP offers great potential since it can be carried out employing DC and AC electric fields, and neutral and charged particles can be manipulated. This work is focused on the use of insulator based dielectrophoresis (iDEP), a novel dielectrophoretic mode that employs arrays of insulating structures to generate dielectrophoretic forces. Successful micro and nanoparticles manipulation can be achieved employing iDEP, due to its unique characteristics that allow for great flexibility. In this work, microchannels containing arrays of cylindrical insulating posts were employed to concentrate, sort and separate microparticles. Mathematical modeling with COMSOL V R was performed to identify optimal device configuration. Different sets of experiments were carried out employing DC and AC potentials. The results demonstrated that effective and fast particle manipulation is possible by fine tuning dielectrophoretic force and electroosmotic flow.

Electric field induced macroscopic cellular phase of nanoparticles

“…Particles on a substrate will interact through two types of electrically-induced fluid flows: EO flow and EHD flow. 22,26,27 While EO flow is a DC phenomenon, EHD flows arise from both V AC and V DC . 22,26 Interestingly, these effects are expected to produce contrasting flow fields in which EO draws particles together in the plane while EHD flow, despite being short-range attractive, will repel particles at long ranges.…”

Dynamic microparticle manipulation with an electroosmotic flow gradient in low‐frequency alternating current dielectrophoresis

“…It is important to note that this system allows distinguishing particles with a diameter difference of 0.5 μm. This was achieved due to sharper electric field gradients (∇ E 2 ) obtained with diamond posts . Figure B shows three different dielectrophoretic behaviors obtained when the signal is 0 V/+900 V. As illustrated in Eq.…”

On the potential of microscale electrokinetic cascade devices

“…Our group has explored insulating post shape and how it impacts particle trapping [21], making posts narrower and wider in an attempt to improve particle trapping [22], and optimization of longitudinal and latitudinal spacing for particle trapping [23]. Overall, these studies demonstrate that variations in post shapes and arrangements can be used to optimize particle separation.…”