In this paper, we present a novel, simple lab-on-a-chip device for continuous separation of parti... more In this paper, we present a novel, simple lab-on-a-chip device for continuous separation of particles by size. The device is composed of a straight rectangular microchannel connecting two inlet reservoirs and two exit reservoirs. Two asymmetric, 3-D electrodes are embedded along the channel wall to generate a non-uniform electrical field for dielectrophoresis. Particles with different sizes are collected at the different exit reservoirs. Main flow is induced by pressure difference between the inlet and the exit reservoirs. The device is used successfully for the separation of the 5 and 10 μm latex particles and for the separation of yeast cells and white blood cells. A numerical simulation based on Lagrangian tracking method is used to simulate the particle motion and the results showed a good agreement with the experimental data.
DC-Dielectrophoresis (DC-DEP), the induced motion of the dielectric particles in a spatially non-... more DC-Dielectrophoresis (DC-DEP), the induced motion of the dielectric particles in a spatially non-uniform DC electric field, is applied to separate biological cells by size. The locally non-uniform electric field is generated by an insulating hurdle fabricated within a PDMS microchannel. The cells experience a negative DEP (accordingly a repulsive) force at the corners of the hurdle where the gradient of local electric-field strength is the strongest. The DC-DEP force acting on the cells is proportional to the cells’ size. Thus the moving cells deviate from the streamlines and the degree of deviation is dependent on the cell size. In this paper, we demonstrated by using this method that, combined with the electroosmotic flow, mixed biological cells of a few to tens of micrometers difference in diameter can be continuously separated into different collecting wells. For separating target cells of a specific size, all that is required is to adjust the voltage outputs of the electrodes.
This study demonstrates an on-chip resistive pulse-sensing scheme with a design of symmetric mirr... more This study demonstrates an on-chip resistive pulse-sensing scheme with a design of symmetric mirror channels, which significantly reduces the noise and achieves better signal-to-noise ratio. Polystyrene particles of different sizes have been detected with the developed sensing scheme and a record low volume ratio of the particle to the sensing channel, or 0.0004%, has been detected with particles of 520 nm in diameter in a sensing aperture of 50×16×20 μm3. This volume ratio is about ten times lower than the lowest volume ratio reported in the literature including that specified for commercial Coulter counters.
In this paper, we present a novel, simple lab-on-a-chip device for continuous separation of parti... more In this paper, we present a novel, simple lab-on-a-chip device for continuous separation of particles by size. The device is composed of a straight rectangular microchannel connecting two inlet reservoirs and two exit reservoirs. Two asymmetric, 3-D electrodes are embedded along the channel wall to generate a non-uniform electrical field for dielectrophoresis. Particles with different sizes are collected at the different exit reservoirs. Main flow is induced by pressure difference between the inlet and the exit reservoirs. The device is used successfully for the separation of the 5 and 10 μm latex particles and for the separation of yeast cells and white blood cells. A numerical simulation based on Lagrangian tracking method is used to simulate the particle motion and the results showed a good agreement with the experimental data.
DC-Dielectrophoresis (DC-DEP), the induced motion of the dielectric particles in a spatially non-... more DC-Dielectrophoresis (DC-DEP), the induced motion of the dielectric particles in a spatially non-uniform DC electric field, is applied to separate biological cells by size. The locally non-uniform electric field is generated by an insulating hurdle fabricated within a PDMS microchannel. The cells experience a negative DEP (accordingly a repulsive) force at the corners of the hurdle where the gradient of local electric-field strength is the strongest. The DC-DEP force acting on the cells is proportional to the cells’ size. Thus the moving cells deviate from the streamlines and the degree of deviation is dependent on the cell size. In this paper, we demonstrated by using this method that, combined with the electroosmotic flow, mixed biological cells of a few to tens of micrometers difference in diameter can be continuously separated into different collecting wells. For separating target cells of a specific size, all that is required is to adjust the voltage outputs of the electrodes.
This study demonstrates an on-chip resistive pulse-sensing scheme with a design of symmetric mirr... more This study demonstrates an on-chip resistive pulse-sensing scheme with a design of symmetric mirror channels, which significantly reduces the noise and achieves better signal-to-noise ratio. Polystyrene particles of different sizes have been detected with the developed sensing scheme and a record low volume ratio of the particle to the sensing channel, or 0.0004%, has been detected with particles of 520 nm in diameter in a sensing aperture of 50×16×20 μm3. This volume ratio is about ten times lower than the lowest volume ratio reported in the literature including that specified for commercial Coulter counters.
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Papers by Yuejun Kang