Design, Fabrication and Experimental Study of Spiral Microchannel Particle Separator on Centrifugal Microfluidic Platforms

Nowadays there are a lot of tendencies to use analytical micro-systems in the field of molecular and microbial diagnostics, because of benefits such as less required space, reduced sample and reagent consumption and shorter analysis time. The rotational microfluidic is a sub-branch of the microfluidic systems which by using centrifugal forces, causes the fluid to flow in the networks enclosed in disk-shaped rotating systems. These networks can carry out chemical or biological tests and lead to create more capable devices replaced with current regular devices for medical diagnosis. One of the most commonly used elements in microfluidic systems is the separation element. This element is used to separate particles in the sample by considering mechanical, chemical and electrical specifications. In this study, a novel geometry designed to seperate particles passively in microfluidic systems. The spiral microchannel geometry imports the local centrifugal force caused by the curvature of the channel in addition to the centrifugal and the Coriolis forces, to affect the particles and increase the efficiency of the separation. At first, the particle separation process in the proposed channel studied. Then the effect of the channel length and rotational velocity parameters on the separation efficiency investigated. The results of the experiments showed that the separation efficiency is above 90%, which indicates the high potential of this element in the process of separation. Also, It was observed that the increase in rotational velocity and the length of the spiral channel improves the process of separation and increases the efficiency.