Microfluidic Chip for Particle-Liquid Separation

Abstract

This paper presents theoretical analysis, design, fabrication and test of a microfluidic device (‘Micro hydrocyclone’) for separation of micron and sub-micron size solid particles from liquid in a particle-liquid mixture. A theoretical analysis of the micro hydrocyclone is performed to understand the physics and develop suitable design models. The structure of the proposed device is designed based on Bradley model, as it offers lower cut-size thus making it suitable for microfluidics applications. The operational parameters are derived from the dimensional group model. The device is fabricated with SU-8 photoresist on PMMA substrate using a combination of photolithography and micro-milling. Experiments are performed to demonstrate particle-liquid separation using polystyrene microbeads suspended in PBS as the feed sample. The influence of inlet velocity and particle size on particle separation efficiency is investigated. The proposed device can be easily integrated with micro-environments thus is suitable for lab-on-chip and microsystems development. The device may have applications in chemical analysis, materials research, point-of-care, blood sample preparation and other biomedical applications.