High-purity DEP-based multitarget separation of particles in a converging microchannel

Background

Dielectrophoresis (DEP) is an efficient, non-invasive method for particle separation. However, most DEP devices focus on binary separation, and achieving high-purity multitarget separation remains challenging. This paper presents the design, fabrication, and characterization of a novel microfluidic device with a converging microchannel for DEP-based multiple-particle separation.

Methods

A custom-developed computational fluid dynamics (CFD) solver within the OpenFOAM framework was used to investigate the influence of various geometrical and operational parameters on particle separation. The design derived from numerical analysis was used to fabricate the microdevice. Experimental particle trajectories were tracked under varying conditions and compared with numerical results. The device performance was evaluated by simultaneously separating a mixture containing three different particle groups.

Significant Findings

A thorough comparison between experimental and numerical findings validated the high accuracy of the developed simulation model. The microdevice achieved separation purities exceeding 97 % for mixtures of 5–10–15 µm, 5–10–20 µm, and 10–15–20 µm particles at a flow rate of 3 µl/min and specific voltages (18.5 Vpp for the first two mixtures and 16 Vpp for the third). In addition to high purity, recovery rates above 95 % were also achieved for all tested mixtures at the same flow rate, confirming efficient particle collection. Furthermore, the analysis of particle trajectory deviations for sizes 5, 10, 15, and 20 µm indicates that, with further development and increasing the number of outlets to four, high-purity separation of these four particle populations can be achieved.