Sheath‐assisted versus sheathless dielectrophoretic particle separation

Abstract

Lab‐on‐chip devices are widely being used for binary and ternary cell/particle separation applications. Among the lab‐on‐chip methods, dielectrophoresis (DEP) is a cost‐effective and label‐free method, with great capabilities for size‐based separation of cells and particles, which is mostly performed in sheath‐assisted forms. However, the elimination of the sheath flows offers advantages such as ease of operation and higher sample throughput. In this work, we present a comparison of sheath‐assisted and sheathless DEP separation of three sizes of microparticles using tilted electrodes. The sheath‐assisted design was capable of separating the 5, 10, and 15 μm particles with a separation efficiency as high as 98.0% for 15 μm particles. By adding a DEP focusing region, a sheathless DEP separator was proposed, which offered higher throughputs (up to 10 times) at the cost of lowering the separation efficiency (a reduction up to 10.3% for 15 μm) compared to the sheath‐assisted design. To enhance the separation efficiency, a combination of the DEP focusing accompanied by weak sheath flows from both sides was proposed. This design achieved the highest sample separation yield in the outlets (as high as 98.7% for 15 μm) with a sample throughput of more than 4.2 μL/min. This study provides insights into the choice of an appropriate platform for any application in which the yield, purity, throughput, and portability must be considered.

Continuous size-based DEP separation of particles using a bi-gap electrode pair

“…They also simulated the continuous separation of three groups of bio-particles, including platelets, red blood cells (RBC), and white blood cells (WBC). Dalili and Hoorfar 35 investigated the performance of sheath-assisted and sheathless microfluidic devices containing planar angled electrode arrays to separate three different populations of polystyrene particles according to their size (5, 10, and 15 μm). The results showed that the sheathless design could achieve the highest throughput while the weak sheath-assisted design could achieve the highest yield and purity.…”