Abstract
We present the integration of a flow focusing microfluidic device in a dielectrophoretic application that based on a tapered aluminum microelectrode array (TAMA). The characterization and optimization method of microfluidic geometry performs the hydrodynamic flow focusing on the channel. The sample fluids are hydrodynamically focused into the region of interest (ROI) where the dielectrophoresis force (FDEP) is dominant. The device geometry is designed using 3D CAD software and fabricated using the micro-milling process combined with soft lithography using PDMS. The flow simulation is achieved using COMSOL Multiphysics 5.5 to study the effect of the flow rate ratio between the sample fluids (Q1) and the sheath fluids (Q2) toward the width of flow focusing. Five different flow rate ratios (Q1/Q2) are recorded in this experiment, which are 0.2, 0.4, 0.6, 0.8 and 1.0. The width of flow focusing is increased linearly with the flow rate ratio (Q1/Q2) for both the simulation and the experiment. At the highest flow rate ratio (Q1/Q2 = 1), the width of flow focusing is obtained at 638.66 µm and at the lowest flow rate ratio (Q1/Q2 = 0.2), the width of flow focusing is obtained at 226.03 µm. As a result, the flow focusing effect is able to reduce the dispersion of the particles in the microelectrode from 2000 µm to 226.03 µm toward the ROI. The significance of flow focusing on the separation of particles is studied using 10 and 1 µm polystyrene beads by applying a non-uniform electrical field to the TAMA at 10 VPP, 150 kHz. Ultimately, we are able to manipulate the trajectories of two different types of particles in the channel. For further validation, the focusing of 3.2 µm polystyrene beads within the dominant FDEP results in an enhanced manipulation efficiency from 20% to 80% in the ROI.
Highlights
As a solution to this problem, we proposed the integration of a hydrodynamic flow focusing technique to reduce the particle dispersion that involves a tapered aluminum microelectrode array (TAMA) in an FDEP
We focus on the characterization and optimization of a hydrodynamic flow focusing technique on a TAMA DEP design application
Area covered by particles of particle 519,422.8 manipulation and separation efficiency for a TAMA profile microelectrode
Summary
The manipulation and separation of targeted particles from their sample play an essential role in biomedical analysis. Recent developments in microfluidic technology and the manipulation and separation of particles can be achieved on a chip. The advantages of this method are portability, only a small amount of sample is required, low cost and low time consumption compared with the conventional method [1,2]. Active techniques use an external field to manipulate the movement of the particle while the passive technique involves the interaction between the microchannel structure and the flow field to manipulate the particles. To support the present work, a hydrodynamic flow focusing technique, Tanyeri et al
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