Issue 19, 2017

Anisotropic permeability in deterministic lateral displacement arrays


We uncover anisotropic permeability in microfluidic deterministic lateral displacement (DLD) arrays. A DLD array can achieve high-resolution bimodal size-based separation of microparticles, including bioparticles, such as cells. For an application with a given separation size, correct device operation requires that the flow remains at a fixed angle to the obstacle array. We demonstrate via experiments and lattice-Boltzmann simulations that subtle array design features cause anisotropic permeability. Anisotropic permeability indicates the microfluidic array's intrinsic tendency to induce an undesired lateral pressure gradient. This can cause an inclined flow and therefore local changes in the critical separation size. Thus, particle trajectories can become unpredictable and the device useless for the desired separation task. Anisotropy becomes severe for arrays with unequal axial and lateral gaps between obstacle posts and highly asymmetric post shapes. Furthermore, of the two equivalent array layouts employed with the DLD, the rotated-square layout does not display intrinsic anisotropy. We therefore recommend this layout over the easier-to-implement parallelogram layout. We provide additional guidelines for avoiding adverse effects of anisotropy on the DLD.

Graphical abstract: Anisotropic permeability in deterministic lateral displacement arrays

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Article information

Article type
26 Jul 2017
22 Aug 2017
First published
24 Aug 2017
This article is Open Access
Creative Commons BY license

Lab Chip, 2017,17, 3318-3330

Anisotropic permeability in deterministic lateral displacement arrays

R. Vernekar, T. Krüger, K. Loutherback, K. Morton and D. W. Inglis, Lab Chip, 2017, 17, 3318 DOI: 10.1039/C7LC00785J

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