Gravity Driven Deterministic Lateral Displacement for Particle Separation in Microfluidic Devices

Abstract

We investigate the two-dimensional continuous size-based separation of suspended particles in gravity-driven deterministic lateral displacement (g-DLD) devices. The suspended particles are driven through a periodic array of cylindrical obstacles under the action of gravity. We perform experiments covering the entire range of forcing orientations with respect to the array of obstacles and identify specific forcing angles that would lead to vector separation, in which different particles migrate, on an average, in different directions. A simple model, based on the lateral displacement induced on the trajectory of a particle by irreversible particle-obstacle interactions, accurately predicts the dependence of the migration angle on the forcing direction. The results provide design guidance for the development of g-DLD devices. We observe directional locking, which strongly depends on the size of the particle and suggests that relatively small forcing angles are well suited for size-fractionation purposes. We demonstrate excellent separation resolution for a binary mixture of particles at relatively small forcing angles, that is, forcing angles that are close to but smaller than the first transition angle of the larger particles in the mixture.

Rotational separation of non-spherical bioparticles using I-shaped pillar arrays in a microfluidic device

“…Beads (2.5 mm) peaked at B16 ± 1.7% separation at channel 6, whereas the output distribution spread was wide and relatively evenly distributed along channels 4-15. The spread that is observed here seems counter-intuitive to the previous performance of DLD devices, which enables distinct separations 18,21,25 . The observed phenomenon could be due to DLD mixed separation mode and further elaborated in Supplementary Note S1 (refs 26-28).…”

Microfluidics cell sample preparation for analysis: Advances in efficient cell enrichment and precise single cell capture

“…Larger size cells will move laterally toward to the side of channel; smaller particles will flow along the original trajectory. [61][62][63][64][65] DLD arrays allow continuous cancer cell enrichment from peripheral blood. However, the cancer cell purity was still very low after enrichment.…”

Deterministic fractionation of binary suspensions moving past a line of microposts

“…[9,10,18,22,38,39] In previous work, we investigated the mechanisms leading to separation in DLD and demonstrated an alternative operation mode, in which suspended species are driven through a two-dimensional (2D) array of posts by a constant force, specifically gravity (g-DLD). [2,6,12,15,21,30? ? ]…”

“…Previous experiments also established that, as the forcing angle increases (from zero), there is a critical transition angle, above which the particles are able to move across columns in the array. [12] This critical transition angle depends on particle size, thus allowing for separation. Moreover, the highest resolution of separation in a binary mixture was found to occur near the critical transition angle.…”

“…Moreover, the highest resolution of separation in a binary mixture was found to occur near the critical transition angle. [12] These results suggest that a single line or a one-dimensional (1D) array of cylindrical posts in lieu of the entire 2D array, could in principle, be used to fractionate a mixture of particles.…”