www.astesj.com 84 Design and Fabrication of a Dielectrophoretic Cell Trap Array Logeeshan Velmanickam, Dharmakeerthi Nawarathna * Department of Electrical and Computer Engineering, North Dakota State University, Fargo, ND, 58102-6050 A R T I C L E I N F O A B S T R A C T Article history: Received: 01 December, 2016 Accepted: 08 January, 2017 Online: 28 January, 2017 We present a design and fabrication of an integrated micro-fabricated dielectrophoretic (DEP) cell trap array in a microfluidic channel. The cell trap array is capable of isolating target cells in high-throughput manner and producing cell clusters of tunable cell numbers. In this work, we have used commercially available polystyrene beads to show the concept. Bead clusters of various sizes were successfully produced using DEP force (attractive or repulsive). We have found that the number of beads in a cluster depends on the frequency of electric field and the concentration of beads in the mixture. Keywords: Dielectrophoresis Cell isolation Electrode cell trap array Electric field gradient 1. Introduction This report is an extension of work that was originally presented in 2016 IEEE International Conference on Electro Information Technology (EIT) [1]. Cell isolation is one of the basic steps of the devices that are commonly used in the applications such as Point-Of-Care diagnosis, food pathogen screening, and environmental monitoring. [2]. It is desirable that the cell isolation needs to be simple and high-throughput. Among the currently available techniques for cell isolation, FACS (fluorescence activated cell sorting), MACS (magnetic activated cell sorting), laser micro dissection, manual cell picking are the methods that are the most widely used. [3]. FACS is the most commonly used method but, to use FACS to isolate target cells, complete knowledge about the surface proteins of the target cells and other non-target cells in the cell mixture is needed. In FACS, first, a fluorescence dye is selectively attached to a surface protein of the target cell and then the separation of target cells is through the fluorescence [4, 3]. To use MACS in cell isolation, prior knowledge about the target cells are also needed. Briefly, in MACS, the target cells are labeled with magnetic beads and they are separated from the cell mixture by applying a magnetic force [5]. Therefore, the prior knowledge about the surface proteins of the cells in the mixture is required for both FACS and MACS methods [3]. Unfortunately, the information of target cells’ surface proteins is not always available and therefore, both of these methods can only be used to isolate limited number of target cells from cell mixtures. In laser micro-dissection, typically, the operator observes the tissue sample through a microscope and the target cell population area is separated by using laser cutting [6]. In manual cell picking, micro-pipettes are used to pick-up the target cell from a cell mixture by applying a negative pressure [2]. Due to the manual operation, laser micro dissection and manual cell pick up methods are low-throughput and not applicable in most of the applications. These critical limitations in existing cell isolation techniques prevent advancing many important areas of biomedical engineering such as Point-Of-Care diagnosis, food pathogen screening, and environmental monitoring. Therefore, there is an urgent need to develop high-throughput, label-free cell isolation technique. To address this critical need, we have developed a high- throughput and label-free technique for cell isolation. The technique is based on the dielectrophoresis (DEP) and microfluidics. First, we briefly describe DEP and microfluidics below. 2. Theory Dielectrophoresis is a motion of suspensoid particles relative to the suspended medium resulting from polarization forces produced by an inhomogeneous electric field [7-11], which is widely used in many biomedical applications such as medical diagnostics, cell therapeutics and molecular separation [14]. In ASTESJ ISSN: 2415-6698 * Corresponding Author: Dharmakeerthi Nawarathna, Email: dharmakeerthi.nawara@ndsu.edu Advances in Science, Technology and Engineering Systems Journal Vol. 2, No. 1, 84-89 (2017) www.astesj.com Special Issue on Computer Systems, Information Technology, Electrical and Electronics Engineering