Design, realisation and validation of microfluidic stochastic mixers integrable in bioanalytical systems using CFD modeling

In this work we present the design aspects of special microfluidic structures applicable to dilute and transport analyte solutions (such as whole blood) to the sensing area of biosensors. Our goal is to design and realise a reliable microfluidic system which is applicable for effective sample transport and can accomplish simple sample preparation functions such as mixing to ensure homogeneous concentration distribution of the species along the fluidic channel. The behaviour of different chaotic mixers were analysed by numerical modeling and experimentally to determine their efficiency. At first we used the concentration distribution method, however because of numerical diffusion this required higher mesh resolutions. Using the particle tracing method is more efficient according to the experimental results and requires lower computational effort. The microstructures were realised by micro-fabrication in polydimethylsiloxane (PDMS) and integrated into a real microfluidic transport system. The functional performance was verified by biological analyte.