Analytical scale ultrasonic standing wave manipulation of cells and microparticles

Coakley, W. Terence; Hawkes, Jeremy J.; Sobański, M.; Cousins, Caroline M.; Spengler, Johannes

doi:10.1016/s0041-624x(99)00151-1

Cited by 97 publications

(52 citation statements)

References 24 publications

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“…In the analysis, the liquid properties of the buffer solution are taken as the deionized water, r ¼ 998 kg=m 3 , e m ¼ 6:94 Â 10 À10 C=Vm andm ¼ 8:6 Â 10 À4 kg=ms. ClausiusMossotti factor is the function of electrical properties of the particle and the medium and the frequency of the alternating current-field, and its value is changing between À0.5 and 1.0.…”

Section: Resultsmentioning

confidence: 99%

“…To achieve these, various techniques have been developed to be used in microsystems such as optical tweezers [1], magnetophoresis [2], acoustic means [3,4,5] and dielectrophoresis (DEP). Among these, DEP is one of the most popular methods for particle manipulation in microsystems due to (i) its favorable scaling effects [6], (ii) the simplicity of the instrumentation and (iii) its ability to induce both negative and positive forces [7].…”

Section: Introductionmentioning

confidence: 99%

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Continuous particle separation based on electrical properties using alternating current dielectrophoresis

Çetin

2009

Electrophoresis

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A design of a microchannel for continuous separation of particles based on alternating current dielectrophoretic is studied. The geometric design parameters are determined by analyzing the dielectrophoresis force field inside the microchannel corresponding to the most efficient separation. The trajectories of 5 and 10 mm spherical particles are derived analytically using Lagrangian tracking method to examine the feasibility and the effectiveness of the design. The effects of the mean flow velocity inside the channel and the applied voltage across the channel on the performance of the separation are also discussed.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Continuous particle separation based on electrical properties using alternating current dielectrophoresis

Çetin

2009

Electrophoresis

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“…Such technologies include particle separation, fractionation and agglomeration, finding applications in areas such as biotechnology [1,2], material processing [3,4] and filter systems.…”

Section: Introductionmentioning

confidence: 99%

Modelling of particle paths passing through an ultrasonic standing wave

et al. 2004

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Within an ultrasonic standing wave particles experience acoustic radiation forces causing agglomeration at the nodal planes of the wave. The technique can be used to agglomerate, suspend, or manipulate particles within a flow. To control agglomeration rate it is important to balance forces on the particles and, in the case where a fluid/particle mix flows across the applied acoustic field, it is also necessary to optimise fluid flow rate.To investigate the acoustic and fluid forces in such a system a particle model has been developed, extending an earlier model used to characterise the 1-dimensional field in a layered resonator. In order to simulate fluid drag forces, CFD software has been used to determine the velocity profile of the fluid/particle mix passing through the acoustic device. The profile is then incorporated into a MATLAB model. Based on particle force components, a numerical approach has been used to determine particle paths. Using particle coordinates, both particle concentration across the fluid channel and concentration through multiple outlets are calculated.Such an approach has been used to analyse the operation of a microfluidic flow-through separator, which uses a half wavelength standing wave across the main channel of the device. This causes particles to converge near the axial plane of the channel, delivering high and low particle concentrated flow through two outlets, respectively. By extending the model to analyse particle separation over a frequency range, it is possible to identify the resonant frequencies of the device and associated separation performance. This approach will also be used to improve the geometric design of the microengineered fluid channels, where the particle model can determine the limiting fluid flow rate for separation to occur, the value of which is then applied to a CFD model of the device geometry.

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“…This force moves species to the pressure node (at the center of the channel) or anti-node (at the side walls) depending on the acoustic contrast factor of the species which is determined by its density and compressibility with respect to the surrounding fluid. As reported in previous works, this acoustic force has been successfully applied in steady fluid flows to concentrate cells and increase cell-cell contact area, 8 and in a continuous micro-flow to separate cellular species, such as blood cells and lipid particles. 9 Continuous cell separation has recently received increasing interest for some applications such as separation of circulating tumour cells from blood as well as automation and fast optimization of cell separation.…”

Section: Introductionmentioning

confidence: 89%

“…7 A similar phenomenon using ultrasonic waves in microfluidic environment, called acoustophoresis, has also been reported. 8,9 For example, studies have demonstrated the use of acoustophoresis to separate a mixture of microparticles that differ in size. 10,11 Furthermore, an acoustic radiation force can also act on cells based on the differences in density and compressibility of the cells (instead of dielectric properties, as in dielectrophoresis) with respect to the surrounding fluid medium.…”

Section: Introductionmentioning

confidence: 99%

Cell separation and transportation between two miscible fluid streams using ultrasound

2012

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This paper presents a two-stream microfluidic system for transporting cells or micro-sized particles from one fluid stream to another by acoustophoresis. The two fluid streams, one being the original suspension and the other being the destination fluid, flow parallel to each other in a microchannel. Using a half-wave acoustic standing wave across the channel width, cells or particles with positive acoustic contrast factors are moved to the destination fluid where the pressure nodal line lies. By controlling the relative flow rate of the two fluid streams, the pressure nodal line can be maintained at a specific offset from the fluid interface within the destination fluid. Using this transportation method, particles or cells of different sizes and mechanical properties can be separated. The cells experiencing a larger acoustic radiation force are separated and transported from the original suspension to the destination fluid stream. The other particles or cells experiencing a smaller acoustic radiation force continue flowing in the original solution. Experiments were conducted to demonstrate the effective separation of polystyrene microbeads of different sizes (3 lm and 10 lm) and waterborne parasites (Giardia lamblia and Cryptosporidium parvum). Diffusion occurs between the two miscible fluids, but it was found to have little effects on the transport and separation process, even when the two fluids have different density and speed of sound.

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Analytical scale ultrasonic standing wave manipulation of cells and microparticles

Cited by 97 publications

References 24 publications

Continuous particle separation based on electrical properties using alternating current dielectrophoresis

Continuous particle separation based on electrical properties using alternating current dielectrophoresis

Modelling of particle paths passing through an ultrasonic standing wave

Cell separation and transportation between two miscible fluid streams using ultrasound

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