Concentration of Magnetic Beads Utilizing Light-Induced Electro-Osmosis Flow

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Entry by Yuhang Jin, AP225 Fall 2011

Reference

Shih-Mo Yang, Punde Tushar Harishchandra, Tung-Ming Yu, Ming-Huei Liu, Long Hsu, and Cheng-Hsien Liu, IEEE Trans. Magn., 2011, 47, 2418.

Keywords

electro-osmosis flow, light-induced dielectrophoresis, magnetic beads, TiOPc

Introduction

Magnetic beads have wide applications in the separation of biomolecules. Traditional magnetic separation technology involves the use of bulk magnets, which makes scaling down of the device rather inefficient. Other techniques for the manipulation and separation of microparticles, such as optical tweezers and dielectrophoresis, are also limited in their flexibility. Therefore optoelectronic tweezers featuring light-induced method and nonuniform electric field were developed. The simplest design of an optoelectronic tweezer modulates the conductivity of amorphous silicon with dynamic light pattern and hence enables trapping and manipulation of particles. In addition, another approach of microparticle concentration via light-induced electro-osmosis flow was also reported. However, the chips required for those means are generally difficult to fabricate, impeding their convenient implementation in biology.

Previously, the authors presented an easier method for chip fabrication by using organic photoconductive material Y-type TiOPc for the light-induced electro-osmosis flow chip with a region of minimum flow velocity for the trapping and collection of magnetic beads. In this paper, they integrate the TiOPc-based substrate and the light-induced electro-osmosis phenomenon. The fabrication process in single and simple, the illumination light power is small, and the low-frequency kHz region for manipulating magnetic beads widens the scope of TiOPc-based optoelectronic dielectrophoresis chip. The device has been demonstrated to be capable of high-efficiency concentration and enrichment of magnetic microparticles.