Biomedical Microdevices

, Volume 10, Issue 1, pp 55–63

Microfluidic cell counter/sorter utilizing multiple particle tracing technique and optically switching approach

Article

DOI: 10.1007/s10544-007-9109-8

Cite this article as:
Lin, CC., Chen, A. & Lin, CH. Biomed Microdevices (2008) 10: 55. doi:10.1007/s10544-007-9109-8

Abstract

This paper proposes a novel microfluidic system based on a computer controlled digital image processing (DIP) technique and optical tweezers for automatic cell/microparticle recognition, counting and sorting in a continuous flow environment. In the proposed system, the cells/microparticles are focused electrokinetically into a narrow sample stream and are then driven through the region of interest (ROI), where they are recognized and traced in real time using a proprietary DIP system. Synchronized control signals generated by the DIP system are then used to actuate a focused IR laser beam to displace the target cells from the main sample stream into a neighboring sheath flow, which carries them to a downstream collection channel where they are automatically counted. Experimental trials show that the microchip is capable of continuously sorting and counting microparticles with diameters of 5 and 10 μm. In addition, a sample composed of yeast cells and polystyrene (PS) beads is successfully sorted and collected with a 100% of yield ratio and 91.9% of recovery ratio. The proposed system provides a simple, low-cost, high-performance solution for cell manipulation in microfluidic devices.

Keywords

MicrofluidicsMicroparticleDigital image processingElectrokinetic focusOptical tweezers

Abbreviations

\( \overline{V} \)

particle velocity within the electric-driven flow (pixel/s)

\( \overline{u} \)

particle velocity in the x-axis direction within the electric-driven flow (pixel/s)

\( \overline{v} \)

particle velocity in the y-axis direction within the electric-driven flow (pixel/s)

P

particle position (pixel)

t

time (s)

Δt

time interval between two consequent image frame (s)

η

viscosity of the buffer liquid (N·s/m2)

v

fluid velocity of the electric-driven flow (m/s)

r

radius of particle

Nomenclature

BOE

buffered oxide etchant

CCD

charge coupled device

DI

deionized water

DIP

digital image processing

FACS

fluorescence-activated cell sorters

HCL

hydrogen chloride

HMI

human–machine interface

IR

infrared

LIF

laser induced fluorescence

MEMS

micro-electro-mechanical-systems

mM

millimolar

N.A.

numerical aperture

PC

personal computer

ROI

region of interest

V

volt

Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  1. 1.Department of Mechanical and Electro-mechanical EngineeringNational Sun Yat-sen UniversityKaohsiungRepublic of China
  2. 2.Institute of Biomedical SciencesNational Sun Yat-sen UniversityKaohsiungRepublic of China
  3. 3.Advanced Crystal Opto-electronics Research CenterNational Sun Yat-sen UniversityKaohsiungRepublic of China