Microparticles manipulation and enhancement of their separation in pinched flow fractionation by insulator‐based dielectrophoresis

Abstract

The separation and manipulation of microparticles in lab on a chip devices have importance in point of care diagnostic tools and analytical applications. The separation and sorting of particles from biological and clinical samples can be performed using active and passive techniques. In passive techniques, no external force is applied while in active techniques by applying external force (e.g. electrical), higher separation efficiency is obtained. In this article, passive (pinched flow fractionation) and active (insulator-based dielectrophoresis) methods were combined to increase the separation efficiency at lower voltages. First by simulation, appropriate values of geometry and applied voltages for better focusing, separation, and lower Joule heating were obtained. Separation of 1.5 and 6 μm polystyrene microparticles was experimentally obtained at optimized geometry and low total applied voltage (25 V). Also, the trajectory of 1.5 μm microparticles was controlled by adjusting the total applied voltage.

Simultaneous isolation and label‐free identification of bacteria using contactless dielectrophoresis and Raman spectroscopy

“…In contrast, many microfluidic devices are designed for only one function, either isolation or identification. For example, many microfluidic DEP devices are solely designed for cell sorting which could be followed by an identification method not carried out within the study . On the other hand, many identification methods, such as Raman spectroscopy , PCR , or FTIR , already assume a sample free of debris, making them ill‐equipped to handle environmental or clinical samples which are bound to have debris.…”

Label-free microfluidic sorting of microparticles

“…Particles were subsequently separated efficiently according to their size and density. Similarly, the separation gap between two particles in the PFF device can be further amplified by adding a dielectrophoretic field, which was demonstrated in a recent work for the separation of 1.5 and 6 μ m particles 134 . Although inertial force is usually unflavored in PFF, 46 Lu and Xuan 135 showed that the separation gap between particles was increased as inertia became stronger in their modified PFF device with an extensively elongated pinched segment (2 cm), and thus, better separation was achieved.…”

Highly efficient removal of ammonia nitrogen from wastewater by dielectrophoresis-enhanced adsorption

“…8 ). This mechanism is supported by the working principle of DEP—a technique that has been used to manipulate polarized particles suspended in fluid media in non-uniform electric field ( Khashei et al, 2015 ). In the case of a spherical particle, the DEP force F DEP is given by the equation below: Where the real part of Clausius–Mossotti factor, Re[ K (ω)], is defined as: Where R denotes the radius of the particle, ∇ E the magnitude of the electric field gradient, ε p * the complex permittivity of the particle, and ε m * that of the media.…”