Dielectrophoretic manipulation of particle mixtures employing asymmetric insulating posts

Abstract

Electrophoresis 2016, 37, 282–290. DOI: 10.1002/elps.201500195 Insulator-based dielectrophoretic (iDEP) devices have proven to be effective for the enrichment and separation of cells and particles. However, conventional iDEP separations are limited by the smallest particles present in the sample. These systems usually require high applied voltages to first concentrate at the post array all particles and then release them gradually by lowering the applied potential. Smaller particles are released first, and larger particles are released last. In this scenario, larger cells are likely subjected to high and prolonged electric field magnitudes, which can lead to considerable cell damage. This study proposes a novel design for an iDEP device where asymmetric insulating posts are coupled with DC-biased AC electric fields to invert the elution order, i.e., larger particles and cells are eluted first. This technique is limited by the largest particle in the sample, so that small voltages are initially applied and are gradually increased to concentrate and enrich larger particles at the outlet of the post array, and elute them, before other particles are eluted. The post asymmetry drives larger particles towards the outlet, while the applied negatively DC-biased AC signal drives smaller particles towards the inlet. The proposed device was designed to separate larger cells quickly by concentrate them in a single location, followed by an effective elution, while retaining a high viability (~85%).