Use of combined dielectrophoretic/electrohydrodynamic forces for biosensor enhancement

Abstract

Dielectrophoretic and electrohydrodynamic forces have been demonstrated in the literature to cause the movement of particles across the surface of planar electrodes when exposed to low-frequency (approx. 1kHz) electric fields. In this paper we describe the development of this phenomenon for the collection of particles, covering a range of sizes, out of a liquid and focusing them at the centercentre of a novel electrode consisting of large interlocking circles. The volume of analyte across which this effect is observed is significantly larger than has been reported for conventional dielectrophoretic arrays. By altering the experimental conditions, particles can either be collected or cycled across the surface and then removed. This technique offers great scope for the enhancement of surface-based detection methods.

On-chip collection of particles and cells by AC electroosmotic pumping and dielectrophoresis using asymmetric microelectrodes

“…Similar results have been reported using devices with large circular electrode pads over which cells and particles were trapped. [7][8][9][10][11]25 The results are consistent with ACEO pumping models predicting that the optimal pumping widths are 1.5Â, 6.55Â, and 4.74Â for the small electrode, large electrode, and large gap, respectively, 34 so configuration 1, with feature dimensions of 1Â, 6Â, and 3Â, is most effective in generating strong unidirectional fluid velocity. 17,19,23,31,34,35 …”

“…The typical microfluidic devices require cells or other analytes to be physically bound or brought close to the surface of a particular transducer to increase the accuracy of detection. Surface-bound microfluidic devices have been successfully coupled with chemical [1][2][3][4][5] and optical [6][7][8][9][10][11][12][13] transducers to rapidly detect cells and particles in microliter suspensions. However, in order to achieve rapid detection, the time for establishing diffusion equilibrium of the analyte to the transducer should be kept to a minimum, requiring small fluidic chamber heights and, consequently, small sample volumes.…”

“…The new configuration is more efficient and compatible with evanescent wave sensing devices. [6][7][8]12,28 We report the characterization of this particle/cell collection device with regard to chamber height, applied potentials, frequency, electrode geometry, electrode and gap width, repetition of asymmetric electrode patterns, and electrolyte concentration. We also introduce techniques combining ACEO with DEP to improve the performance of the device for collecting particles and cells from suspension.…”

Rapid, automated measurement of dielectrophoretic forces using DEP‐activated microwells

“…This choice was made because the DEP spectrum of yeasts has been widely measured in previous work [12,[22][23][24] including that from our laboratory (REFS), allowing it to be used as a reference. The yeast cells …”

Enhancing the Performance of Surface-based Biosensors by AC Electrokinetic Effects - a Review

“…Due to the range of effective frequencies, voltages and ease of application, a number of researchers have proposed techniques to enhance the activity of microfluidic sensors by using AC electrohydrodynamic flows (Sigurdson et al, 2005;Hoettges et al, 2003;Gagnon & Chang, 2005;Wu et al, 2005a;Sauli et al, 2005;Hou et al, 2007;Wu et al, 2005b). This chapter will review the use of AC electrokinetics to develop biosensors for pathogens as well as the different detection techniques employed.…”