Pillar based microfluidic approach to sorting of microparticle mixtures at various particle ratios

Abstract

In this work, we report a microfluidics-based approach to the sorting of two-particle and three-particle mixtures using a micropillar arrangement. Using a simple retain-and-release strategy, we demonstrate the capability of the device to completely sort two-particle mixtures containing particles at various ratios. Additionally, for three-particle mixture, we demonstrate enrichment and recovery of largest size particles and generation of streams completely free of the largest particles. The efficiency of the sorting process is characterized in terms of purity and recovery using Fluorescence Activated Cell Sorting (FACS). We report high purity and recovery of the target particles for all the particle ratios investigated and the particle release strategy employed here is observed to be crucial to this. Through a systematic investigation on the effect of particle ratios on the sorting process, the present work demonstrates the ability of pillar-based microfluidic devices to sort microparticles in diverse applications, beyond the usual blood cell sorting application.