| 1. |
- Garofalo, Fabio, et al.
(författare)
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Statistic estimation of cell compressibility based on acoustophoretic separation data
- 2020
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Ingår i: Microfluidics and Nanofluidics. - : Springer Science and Business Media LLC. - 1613-4982 .- 1613-4990. ; 24:8
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Tidskriftsartikel (refereegranskat)abstract
- We present a new experimental method that measures the compressibility of phenotype-specific cell populations. This is done by performing statistical analysis of the cell counts from the outlets of an acoustophoresis chip as a function of the increasing actuator voltage (i.e. acoustic energy density) during acoustophoretic separation. The theoretical separation performance curve, henceforth, Side-Stream Recovery (SSR), vs the piezo-actuator voltage (V) is derived by moment analysis of a one-dimensional model of acoustophoresis separation, accounting for distributions of the cell or microparticle properties and the system parameters (hydrodynamics, radiation force, drag enhancement, and acoustic streaming). The acoustophoretic device is calibrated with polymer microbeads of known properties by fitting the experimental SSR with the theoretical SSR , in which the acoustic energy density is considered proportional to the squared voltage, i.e. Eac=αV2. The fitting parameter α for the calibration procedure is the device effectivity, reflecting the efficiency in performing acoustophoretic microparticle displacement. Once calibrated, the compressibility of unknown cells is estimated by fitting experimental SSR cell data points with the theoretical SSR curve. In this procedure, the microparticle compressibility is the fitting parameter. The method is applied to estimate the compressibility of a variety of cell populations showing its utility in terms of rapid analysis and need for minute sample amounts.
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| 2. |
- Valijam, Shayan, et al.
(författare)
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Design of a low-voltage dielectrophoresis lab-on-the chip to separate tumor and blood cells
- 2023
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Ingår i: Microfluidics and Nanofluidics. - : Springer Berlin/Heidelberg. - 1613-4982 .- 1613-4990. ; 27:3
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we design and propose a compact label-free microfluidic lab-on-a-chip device to separate circulating tumor cells (CTCs) from red blood cells (RBCs) at low voltage to minimize cell damage. With the aim of developing a mm-long device to perform cell separation, we used 3D finite element simulation modeling and investigated separation efficiency for different electrode configurations, electrode shapes, and channel heights. Our results show that configuring the electrodes as two arrays, consisting of only five pairs of top and bottom planar electrodes shifted relative to each other and energized with ± 6 V at 70 kHz, generates sufficient non-uniform electric fields to separate CTCs and RBCs in a 2 mm long channel. The advantage of the proposed design is the simplicity of the electrode arrangement and that the electrodes do not cover the central part of the channel, thus allowing for brightfield imaging of the channel. In addition, the low voltage needed and the 50 µm high channel reduce the Joule heating effect and improve the device's separation and throughput efficiency. We suggest that the proposed design would be effective for separating CTCs and RBCs and, thus, used as a device for the early detection of CTCs.
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| 3. |
- Sachs, Sebastian, et al.
(författare)
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On the behavior of prolate spheroids in a standing surface acoustic wave field
- 2023
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Ingår i: Microfluidics and Nanofluidics. - 1613-4982. ; 27:12
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Tidskriftsartikel (refereegranskat)abstract
- The active manipulation of particle and cell trajectories in fluids by high-frequency standing surface acoustic waves (sSAW) allows to separate particles and cells systematically depending on their size and acoustic contrast. However, process technologies and biomedical applications usually operate with non-spherical particles, for which the prediction of acoustic forces is highly challenging and remains a subject of ongoing research. In this study, the dynamical behavior of prolate spheroids exposed to a three-dimensional acoustic field with multiple pressure nodes along the channel width is examined. Optical measurements reveal an alignment of the particles orthogonal to the pressure nodes of the sSAW, which has not been reported in literature so far. The dynamical behavior of the particles is analyzed under controlled initial conditions for various motion patterns by imposing a phase shift on the sSAW. To gain detailed understanding of the particle dynamics, a three-dimensional numerical model is developed to predict the acoustic force and torque acting on a prolate spheroid. Considering the acoustically induced streaming around the particle, the numerical results are in excellent agreement with experimental findings. Using the proposed numerical model, a dependence of the acoustic force on the particle shape is found in relation to the acoustic impedance of the channel ceiling. Hence, the numerical model presented herein promises high progress for the design of separation devices utilizing sSAW, exploiting an additional separation criterion based on the particle shape.
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