Three dimensional passivated-electrode insulator-based dielectrophoresis

Abstract

In this study, a 3D passivated-electrode, insulator-based dielectrophoresis microchip (3D pDEP) is presented. This technology combines the benefits of electrodebased DEP, insulator-based DEP, and three dimensional insulating features with the goal of improving trapping efficiency of biological species at low applied signals and fostering wide frequency range operation of the microfluidic device. The 3D pDEP chips were fabricated by making 3D structures in silicon using reactive ion etching. The reusable electrodes are deposited on second glass substrate and then aligned to the microfluidic channel to capacitively couple the electric signal through a 100 lm glass slide. The 3D insulating structures generate high electric field gradients, which ultimately increases the DEP force. To demonstrate the capabilities of 3D pDEP, Staphylococcus aureus was trapped from water samples under varied electrical environments. Trapping efficiencies of 100% were obtained at flow rates as high as 350 ll/h and 70% at flow rates as high as 750 ll/h. Additionally, for live bacteria samples, 100% trapping was demonstrated over a wide frequency range from 50 to 400 kHz with an amplitude applied signal of 200 Vpp. 20% trapping of bacteria was observed at applied voltages as low as 50 Vpp. We demonstrate selective trapping of live and dead bacteria at frequencies ranging from 30 to 60 kHz at 400 Vpp with over 90% of the live bacteria trapped while most of the dead bacteria escape. V C 2015 AIP Publishing LLC.

On the recent developments of insulator‐based dielectrophoresis: A review

“…Furthermore, trapping efficiencies of 100% and flow rates as high as 10 μL/min were achieved with this configuration. In a more recent report, the Agah groups also demonstrated a 3D configuration (Section ). The Agah group also developed the off‐chip passivated‐electrode iDEP (OπDEP) mode , which is similar to EπDEP with the added advantage that the electrodes are located on a reusable platform that is combined with a disposable inexpensive platform that contains the insulating posts.…”

“…Another creative approach called embedded passivated‐electrode iDEP (EπDEP) was proposed by the Agah research group . This hybrid dielectrophoretic mode combines iDEP and eDEP as it employs devices that contain both electrodes and insulating structures.…”

Isolation and enrichment of low abundant particles with insulator-based dielectrophoresis

“…They coined this technique 3D pDEP. With this novel device, Nakidde et al 19 studied the trapping efficiency of biological cells (Staphylococcus aureus) using low applied electrical signals and varying frequencies. They found that by combining electrodes with insulating posts, the trapping efficiency for bacterial cells could be increased significantly at lower applied voltages than those required with conventional iDEP systems.…”

“…Tumor initiating prostate cells were successfully collected without the need of extensive sample preparation or cell labeling, 17 and leukemia cells were continuously sorted from diluted blood samples. 18 Nakidde et al 19 employed a device that combined the characteristics of eDEP and iDEP by featuring 3D insulating cylindrical microposts and passivated electrodes. They coined this technique 3D pDEP.…”

Development of three-dimensional integrated microchannel-electrode system to understand the particles' movement with electrokinetics

“…The DEP force exerting on the dielectric particles in non-uniform electric fields is widely used to manipulate the particles. [9][10][11][12][13] Conventionally, in the manipulation technique with electrical method using DEP force, the particles are immersed in low conductivity fluid. However, the low conductivity fluid is not consistent with the natural environment of cells which is highly conductive.…”