Electrokinetically-driven deterministic lateral displacement for particle separation in microfluidic devices

TL;DR

This paper introduces an electrokinetically-driven deterministic lateral displacement (e-DLD) microfluidic device that enables continuous, high-resolution two-dimensional particle separation by controlling electric field orientation and exploiting particle-obstacle interactions.

Contribution

The study presents a novel electrokinetic approach for particle separation in microfluidics, including a simple model to predict particle migration based on obstacle interactions and field orientation.

Findings

Particles of different sizes migrate in distinct directions at specific forcing angles.

Directional locking and sharp transition phenomena enhance separation resolution.

The model accurately predicts particle migration angles based on field orientation.

Abstract

An electrokinetically-driven deterministic lateral displacement (e-DLD) device is proposed for the continuous, two-dimensional fractionation of suspensions in microfluidic platforms. The suspended species are driven through an array of regularly spaced cylindrical posts by applying an electric field across the device. We explore the entire range of orientations of the driving field with respect to the array of obstacles and show that, at specific forcing-angles, particles of different size migrate in different directions, thus enabling continuous, two-dimensional separation. We discuss a number of features observed in the kinetics of the particles, including directional locking and sharp transitions between migration angles upon variations in the direction of the force, that are advantageous for high-resolution two-dimensional separation. A simple model based on individual particle-obstacle interactions accurately describes the migration angle of the particles depending on the orientation of the driving field, and can be used to re-configure driving field depending on the composition of the samples.