Microfluidics and Nanofluidics

, Volume 8, Issue 2, pp 217–229

Separation of micro-particles utilizing spatial difference of optically induced dielectrophoretic forces

Research Paper

DOI: 10.1007/s10404-009-0457-y

Cite this article as:
Lin, WY., Lin, YH. & Lee, GB. Microfluid Nanofluid (2010) 8: 217. doi:10.1007/s10404-009-0457-y

Abstract

This paper presents new methods to accurately separate micro-particles with different sizes using optically induced dielectrophoretic (ODEP) forces. It is found that the strength of the ODEP force induced on the hydrogenated amorphous silicon surface is determined by the color, line-width and intensity of the optical beams, which provide an innovative design for particle separation. Two linear-segment virtual electrodes which produced the ODEP forces were firstly defined by illuminating lights onto a photoconductive chip. One moving line and one stationary illuminated line were used to generate a stronger and a weaker ODEP force, respectively. The micro-particles were then continuously pushed forward by the stronger ODEP force. As these lines approached each other, larger micro-particles entrained by the higher ODEP forces were squeezed through the stationary electrode and subsequently separated from the smaller particles. With this approach, continuous particle separation can be automatically achieved within a few seconds. This developed method may be promising for a variety of applications such as cell-based assays and sample pretreatment using micro-particles.

Keywords

Optically induced dielectrophoreticParticle separationMicrofluidicsMEMS

Abbreviations

AC

Alternating current

CCD

Charge-coupled device

CM

Clausius–Mossotti

DEP

Dielectrophoretic

DI

Deionized

DNA

Deoxyribonucleic acid

FBS

Fetal bovine serum

IPCE

Incident photon-to-current conversion efficiency

ITO

Indium-tin-oxide

LCD

Liquid crystal display

MEMS

Microelectromechanical system

ODEP

Optically induced dielectrophoretic

OET

Optoelectronic tweezers

PECVD

Plasma enhanced chemical vapor deposition

List of symbols

E

Electric field strength

r

Radius of the spherical particle

v

Terminal velocity of the spherical beads

εm

Electrical permittivity of the surrounding buffer

η

Dynamic viscosity of the fluid

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Department of Engineering ScienceNational Cheng Kung UniversityTainanTaiwan