Size-dependent dielectrophoretic crossover frequency of spherical particles.

Dielectrophoresis (DEP) has been extensively used in lab-on-a-chip systems for trapping, separating, and manipulating of micro particles suspended in a liquid medium. The most widely used analytic model, the dipole model, provides an accurate prediction on the crossover frequency of submicron particles, but cannot explain the significant drop in crossover frequency of larger particles. Here, we present numerical simulations using the Maxwell stress tensor (MST) and finite element method to study the size effect of the DEP crossover frequency of spherical polystyrene particles suspended in de-ionized water. Our results show that the surface conductance due to the electrical double layer plays a key role, and the size dependency of crossover frequency obtained by the MST method agrees reasonably well with published experimental data. The exponents of the power law are approximately -1.0 and -4.3 for smaller (diameter < 4.6 μm) and larger particles (diameter  > 4.6 μm), respectively. The free surface charge distribution reveals that the charge begins accumulating on the particle equator for particle diameters larger than a critical diameter of 4.6 μm, a result not captured by the dipolar approximation. This method may be extended to analyze bioparticles with complex shapes and composition, and provides new insights into the interpretation of dielectrophoresis applications using lab-on-a-chip systems.

[1]  Che-Liang Tsai,et al.  Light-driven manipulation of picobubbles on a titanium oxide phthalocyanine-based optoelectronic chip , 2011 .

[2]  Thomas B. Jones,et al.  Multipolar dielectrophoretic force calculation , 1994 .

[3]  Hsien-Chang Chang,et al.  Antibiotic susceptibility test based on the dielectrophoretic behavior of elongated Escherichia coli with cephalexin treatment. , 2011, Biomicrofluidics.

[4]  H. A. Pohl.  The Motion and Precipitation of Suspensoids in Divergent Electric Fields , 1951 .

[5]  R. Stocker,et al.  Microfluidic characterization and continuous separation of cells and particles using conducting poly(dimethyl siloxane) electrode induced alternating current-dielectrophoresis. , 2011, Analytical chemistry.

[6]  Hywel Morgan,et al.  Dielectrophoresis of Submicrometer Latex Spheres. 1. Experimental Results , 1999 .

[7]  J. L. Sebastian,et al.  Dielectric characterization of bacterial cells using dielectrophoresis , 2007, Bioelectromagnetics.

[8]  Saeid Nahavandi,et al.  Dielectrophoretic-activated cell sorter based on curved microelectrodes , 2010 .

[9]  Torsten Müller,et al.  The influence of higher moments on particle behaviour in dielectrophoretic field cages , 1999 .

[10]  Ming C. Wu,et al.  Massively parallel manipulation of single cells and microparticles using optical images , 2005, Nature.

[11]  D. Vezenov,et al.  Dielectrophoretic tweezers as a platform for molecular force spectroscopy in a highly parallel format , 2011, 2012 38th Annual Northeast Bioengineering Conference (NEBEC).

[12]  S G Shirley,et al.  Dielectrophoretic sorting of particles and cells in a microsystem. , 1998, Analytical chemistry.

[13]  H. Ou-yang,et al.  Direct measurements of the frequency-dependent dielectrophoresis force. , 2009, Biomicrofluidics.

[14]  The dielectrophoresis of cylindrical and spherical particles submerged in shells and in semi-infinite media , 2004 .

[15]  H Morgan,et al.  Measurement of Bacterial Flagellar Thrust by Negative Dielectrophoresis , 1999, Biotechnology progress.

[16]  Donald Wlodkowic,et al.  On-chip separation of Lactobacillus bacteria from yeasts using dielectrophoresis , 2012 .

[17]  C. Rosales,et al.  Numerical comparison between Maxwell stress method and equivalent multipole approach for calculation of the dielectrophoretic force in single‐cell traps , 2005, Electrophoresis.

[18]  D. Land,et al.  Dielectric properties of female human breast tissue measured in vitro at 3.2 GHz. , 1992, Physics in medicine and biology.

[19]  Jonghyun Oh,et al.  Comprehensive analysis of particle motion under non-uniform AC electric fields in a microchannel. , 2009, Lab on a chip.

[20]  M. Ozkan,et al.  Electro-optical platform for the manipulation of live cells , 2003 .

[21]  H. Morgan,et al.  Dielectrophoretic Characterization and Separation of Antibody-Coated Submicrometer Latex Spheres , 1999 .

[22]  P. Hesketh,et al.  Interpretation of ac dielectrophoretic behavior of tin oxide nanobelts using Maxwell stress tensor approach modeling , 2012 .

[23]  Peter R. C. Gascoyne,et al.  General expressions for dielectrophoretic force and electrorotational torque derived using the Maxwell stress tensor method , 1997 .

[24]  Emmanuel Picard,et al.  Determination of Clausius–Mossotti factors and surface capacitances for colloidal particles , 2011 .

[25]  K. Kaler,et al.  A nonequilibrium statistical mechanical calculation of the surface conductance of the electrical double layer of biological cells and its application to dielectrophoresis , 1993 .

[26]  Michael P Hughes,et al.  Dielectrophoretic assay of bacterial resistance to antibiotics. , 2003, Physics in medicine and biology.

[27]  R. Pethig.  Review article-dielectrophoresis: status of the theory, technology, and applications. , 2010, Biomicrofluidics.

[28]  H. P. Robertson,et al.  The Dielectric Behavior of Colloidal Particles with an Electric Double-Layer , 1932 .

[29]  Cheng-Hsien Liu,et al.  Dynamic manipulation and patterning of microparticles and cells by using TiOPc-based optoelectronic dielectrophoresis. , 2010, Optics letters.

[30]  Hughes,et al.  The Dielectrophoretic Behavior of Submicron Latex Spheres: Influence of Surface Conductance. , 1999, Journal of colloid and interface science.