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Multiple Bio-Particle Separation Using a Two-Stage Microfluidic Dielectrophoretic Sorter

Bhandarkar, Sheela
http://rave.ohiolink.edu/etdc/view?acc_num=akron1218821450

Abstract Details

2008, Master of Science in Engineering, University of Akron, Biomedical Engineering.
Cell sorting is one of the critical processes in biomedical analysis and medical diagnostics. One important application is the differential sorting of blood cells widely used as a standard clinical diagnostic tool in the field of hematology. Currently, fluorescent activated cell sorting and magnetic activated cell sorting based sorting are widely used. Both sorting techniques are performed in the laboratory, required skilled personnel, and are thus impractical for real time applications.Dielectrophoresis activated cell sorting (DACS) is one potential technique used in microfluidic devices to sort cells. Dielectrophoresis (DEP) is based upon the polarization phenomenon of suspended particles when a non-uniform electric field is applied. The polarity of the particles is dependent on the particle size, conductivity and permittivity of particles and the suspending medium. The AC electric field frequency plays a prime role in manipulating the polarity of particles and is employed to sort particles. Current dielectrophoretic sorters are able to sort only two types of particles at a time. While in real biological system there are multiple particles coexisting, a particle sorter is needed for applications that require sorting of multiple particles. In my thesis, I present a two stage microfluidic dielectrophoretic sorter for sorting four different types of micro particles using divergent planar electrodes. The microchannels and reservoirs were fabricated on PDMS using soft lithography, and bonded to a glass substrate with patterned Au/Ti electrodes. Experimental conditions including applied voltage, frequency, microchannel dimensions, and flow velocity were optimized to increase sorting efficiency. Four particles, 20μm and 30μm Polystyrene beads, Juniper pollen and Cottonwood pollen all suspended in 0.11mS/min conductivity saline (NaCl) water, were used for testing the sorter. To demonstrate the effect of frequency on particle sorting, experiments were conducted on individual particles and the crossover frequency range at which effective sorting due to positive and negative dielectrophoresis were obtained. When an AC voltage of 10V p-p was applied between the electrodes, the 20μm exhibited positive dielectrophoresis at frequencies below 24 kHz and negative dielectrophoresis at frequencies greater than 32 kHz. Similarly, the 30μm polystyrene particles showed positive dielectrophoresis at frequencies below 5 kHz and negative dielectrophoresis at frequencies above 18 kHz. The Juniper pollen had its positive dielectrophoretic effect at frequencies below 9MHz and negative dielectrophoresis above 14MHz and Cotton wood pollen exhibited positive dielectrophoresis at frequencies below 1MHz and negative dielectrophoresis above 4MHz. The demonstration of sorting process was then conducted. Sorting of two particles in a single stage device by size and material properties was first demonstrated. Finally, we demonstrated sorting of four particles in a two-stage dielectrophoretic sorter. The design concept can be extended to multiple-stage sorter for sorting multiple particles at a time.
Jiang J. Zhe, PhD (Advisor)
94 p.
Biomedical Research; Engineering; Mechanical Engineering
dielectrophoresis; particle sorting; microfluidics; microfabrication

Recommended Citations

Citations

  • Bhandarkar, S. (2008). Multiple Bio-Particle Separation Using a Two-Stage Microfluidic Dielectrophoretic Sorter [Master's thesis, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1218821450

    APA Style (7th edition)

  • Bhandarkar, Sheela. Multiple Bio-Particle Separation Using a Two-Stage Microfluidic Dielectrophoretic Sorter. 2008. University of Akron, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1218821450.

    MLA Style (8th edition)

  • Bhandarkar, Sheela. "Multiple Bio-Particle Separation Using a Two-Stage Microfluidic Dielectrophoretic Sorter." Master's thesis, University of Akron, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1218821450

    Chicago Manual of Style (17th edition)

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This open access ETD is published by University of Akron and OhioLINK.