Microfluidics with new multi-stage arc-unit structures for size-based cross-flow separation of microparticles

Abstract

The cross-flow filtration mechanism is useful to evade the jam of neighboring microstructures for attaining effective separation and/or purification of microparticles. This study presents the design, manufacture and performance check of a new cross-flow microfilter with simple arc-unit structures to passively and continuously separate certain sample microparticles using size variety. We applied ANSYS/Fluent® CFD software to simulate the separation mechanism. The layouts of cross-flow microfilters with the curved angles of 60° and 90° were proposed to analyze the design influence on the particle migration and separation behaviors. We then compared the predicted flow pattern in the microfilter with the visualized particle-streak images taken with a micro-flow visualization system. For verification of the separation effectiveness to illustrate the potential bio-applications of devised cross-flow microfilters, this study further utilized an integrated microfluidic device using dual arc units to achieve multiple filtrations. The fluorescent microparticles at different sizes were imitated blood cells to examine the influences of the geometric configuration, particle concentration of the sample solution and operating flowrate on the separation performance. The testing of the proposed cross-flow microfilter indicated the measured separation efficiency up to 90.1%.