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Biomicrofluidics / Volume 3 / Issue 1 / SPECIAL TOPIC: INVITED PAPERS FROM THE 2009 CONFERENCE ON ADVANCES IN MICROFLUIDICS AND NANOFLUIDICS, THE HONG KONG UNIVERSITY OF SCIENCE & TECHNOLOGY, HONG KONG, 2009 (GUEST EDITOR: WEIJIA WEN)

Biomicrofluidics 3, 012003 (2009); http://dx.doi.org/10.1063/1.3058569 (8 pages)

Direct measurements of the frequency-dependent dielectrophoresis force

Ming-Tzo Wei, Joseph Junio, and H. Daniel Ou-Yang

Physics Department, Lehigh University, Bethlehem, Pennsylvania 18015, USA

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(Received 2 December 2008; accepted 4 December 2008; published online 2 January 2009)

Dielectrophoresis (DEP), the phenomenon of directed motion of electrically polarizable particles in a nonuniform electric field, is promising for applications in biochemical separation and filtration. For colloidal particles in suspension, the relaxation of the ionic species in the shear layer gives rise to a frequency-dependent, bidirectional DEP force in the radio frequency range. However, quantification methods of the DEP force on individual particles with the pico-Newton resolution required for the development of theories and design of device applications are lacking. We report the use of optical tweezers as a force sensor and a lock-in phase-sensitive technique for analysis of the particle motion in an amplitude modulated DEP force. The coherent detection and sensing scheme yielded not only unprecedented sensitivity for DEP force measurements, but also provided a selectivity that clearly distinguishes the pure DEP force from all the other forces in the system, including electrophoresis, electro-osmosis, heat-induced convection, and Brownian forces, all of which can hamper accurate measurements through other existing methods. Using optical tweezers-based force transducers already developed in our laboratory, we have results that quantify the frequency-dependent DEP force and the crossover frequency of individual particles with this new experimental method.

© 2009 American Institute of Physics

Article Outline

  1. INTRODUCTION
  2. EXPERIMENTAL
    1. Materials
    2. Methods
      1. Optical tweezer-based DEP force spectroscopy
      2. The motion of the optically trapped particle in an AM DEP force field
      3. Instrumentation
  3. EXPERIMENTAL RESULTS
  4. CONCLUSIONS

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KEYWORDS and PACS

Keywords

biochemistry, biological techniques, colloids, convection, electrophoresis, force measurement, force sensors, molecular biophysics, osmosis, radiation pressure

PACS

ARTICLE DATA

Digital Object Identifier
http://dx.doi.org/10.1063/1.3058569

PUBLICATION DATA

ISSN

1932-1058 (print)  
1932-1058 (online)

Publisher

$abstract.society.value is a Member of CrossRef American Institute of Physics

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    References

    H. A. Pohl, J. Appl. Phys. 22, 869 (1951)JAPIAU000022000007000869000001.

    H. A. Pohl, J. Appl. Phys. 29, 1182 (1958)JAPIAU000029000008001182000001.

    L. A. Hough and H. D. Ou-Yang, Phys. Rev. E 65, 021906 (2002).

    L. A. Hough and H. D. Ou-Yang, Phys. Rev. E 73, 031802 (2006).

    I. F. Cheng, H. C. Chang, D. Hou, and H.-C. Chang, Biomicrofluidics 1, 021503 (2007)BIOMGB000001000002021503000001.

    P. D. Hoffman and Y. Zhu, Appl. Phys. Lett. 92, 224103 (2008)APPLAB000092000022224103000001.

    J. E. Gordon, Z. Gagnon, and H. C. Chang, Biomicrofluidics 1, 044102 (2007)BIOMGB000001000004044102000001.


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