Continuous separation of colloidal particles using dielectrophoresis

Abstract

Continuous separation of colloidal particles using dielectrophoresisDielectrophoresis is the movement of particles in nonuniform electric fields and has been of interest for application to manipulation and separation at and below the microscale. This technique has the advantages of being noninvasive, nondestructive, and noncontact, with the movement of particle achieved by means of electric fields generated by miniaturized electrodes and microfluidic systems. Although the majority of applications have been above the microscale, there is increasing interest in application to colloidal particles around a micron and smaller. This paper begins with a review of colloidal and nanoscale dielectrophoresis with specific attention paid to separation applications. An innovative design of integrated microelectrode array and its application to flow-through, continuous separation of colloidal particles is then presented. The details of the angled chevron microelectrode array and the test microfluidic system are then discussed. The variation in device operation with applied signal voltage is presented and discussed in terms of separation efficiency, demonstrating 99.9% separation of a mixture of colloidal latex spheres. Keywords:Colloidal / Dielectrophoresis / Separation DOI 10.1002/elps.2012004661 Introduction GeneralDielectrophoresis (DEP) is the motion arising from the interaction of nonuniform electric fields and the induced electrical dipole in polarizable particles [1][2][3][4][5]. The standard electrical technique of electrophoretic separation works when suspended charged particles migrate under the influence of applied electric field. DEP has distinct advantages over this technique in that it can separate neutral particles as well, allowing the separation of particles without having to physiologically alter them; which gives minimum particle handling and no damage. DEP also typically uses microfabricated electrodes to generate highly nonuniform electric fields, which allows it to be performed locally, whereas electrophoretic separation is generally a long-range effect acting between two large external electrodes. Due to the requirements for microfabrication, the localized nature of DEP, and the rapid growth of microfluidic Labon-a-Chip systems or TAS in the past two decades in both research and commercial sectors [6][7][8], there has been a recent growth in the application of DEP to these areas. The first practical application of Lab-on-a-Chip was in fact on-chip CE [9] and with recent advances in the synthesis and the charCorrespondence: Dr. Nicolas Green, Nano Group, School of Electronics and Computer Science, University of Southampton, Highfield, Southampton, SO17 1BJ, UK E-mail: ng2@ecs.soton.ac.uk Fax: +44-2380593029 acterization of size-selected particles in the submicron and nanometer (colloidal) range, an investigation of their physical and chemical properties is now possible [10]. The capability to produce small scale devices allows the development of entirely novel experiments and chip-based analytical system...

Dielectrophoretic Manipulation and Separation of Microparticles Using Microarray Dot Electrodes

“…The basis for generating the DEP force is the interaction between the particle's dipole and the spatial gradient of the electric field [3]. DEP has been extensively employed as a potential technique to manipulate viruses [4], proteins [5], bacteria [6], DNA [7], spores [8], algae [9], parasites [10] and nano-sized latex particles [11]. In addition, DEP has been used in research on cell lysis [12] and to characterize a wide range of yeast cells [13] and mammalian cells, such as neurons [14], leukemia cells [15], platelets [16], cancer cells [17], and sperm cells [18].…”

Cell Patterning for Liver Tissue Engineering via Dielectrophoretic Mechanisms

“…Biological cells as well as microbeads, DNA, protein, bacteria and so on, are good candidates for polarizable particles for manipulation by isolation, characterization, separation, and patterning [61–66]. Innovations in DEP research coupled with advanced microfabrication and microfluidic techniques have introduced methods for developing better tissue engineering tools, primarily for liver.…”

Microarray Dot Electrodes Utilizing Dielectrophoresis for Cell Characterization

“…DEP has also been used in research on apoptosis [36,37] and cell lysis and viability [38–40]. Moreover, the phenomenon has been used to manipulate micro-sized polystyrene particles [41], nano-sized latex particles [42] and biopolymers [43]. DEP has been employed extensively to characterize various mammalian cells such as neurons [44], leukemia cells [45], yeast cells [46], platelets [47], cancer cells [48] and sperm cells [49].…”