Papers by Author: Hou Jin Wu

Abstract: The stabilities of the burst frequencies of the capillary valves have a strong impact on the robustness of sequential flow controls on the centrifugal platform. In this study, factors which influence the burst frequencies of the capillary valves were investigated. It was found that the burst frequencies of the capillary valves were affected by the flow retardation effects. Hydrophobic treatment on the surface of the capillary valve is necessary in order to reduce the retention time of the liquid. In addition, by increasing the depth of the reservoir and conducting hydrophilic treatment on the surface of the reservoir, variations in burst frequencies of the capillary valves can be greatly reduced.

Abstract: This work reports a novel mixing design that can do fast, batch-typed liquid mixing on a centrifugal platform. Mixing is an important procedure for many applications related to chemical reactors and biological assays, especially in the field of microfluidics. The extremely small sizes of microchannels make it difficult to achieve turbulence to assist mixing. To overcome this problem, a meandering fluidic design on the centrifugal platform is proposed. Centrifual force promotes mixing by inducing lateral flow movement in the circular section and flow focusing effect in the bending section. The degree of mixing was studied for solutions with various viscosities under different rotational speeds. The experimental results showed that this mixer can mix microliter or nanoliter volumes of aqueous solutions within one second.