An electrothermal micromixer for molecular analysis

Diffusion is often the rate-limiting step in microfluidic-based biochemical analysis systems. In this paper, an alternative current electrothermal mixer for molecular diagnostic is presented. The mixer consists of a concentric electrode design integrated in a microfluidic cartridge. We investigated the electrothermal flow by visualizing the trajectories of seeded particles. The velocity shows a fourth power voltage dependence and is most efficient in the range of 200-600 kHz. By optimizing the design and operating conditions, we demonstrated enhancement of DNA hybridization with a 60-fold reduction in total assay time.