Rapid mixing achieved using Coriolis force and grooves in rotating microchannels

Mixing is a critical process in reagent reactions used in biomedical applications. Nevertheless, achieving rapid mixing in microfluidics is challenging because of the low-Reynolds region. This study numerically investigated the mixing performance of a rotating channel based on the Coriolis force with herringbone grooves. In the absence of grooves, the mixing was maximized when the Coriolis force was appropriately balanced with the centrifugal force. As the aspect ratio increased from 0.5 to 2.0, rapid mixing was achieved owing to the decreased transverse distance between the rotating flows. Mixing improved with the herringbone grooves, achieving up to >90% for the shortest channel length (20 mm) among the various microchannels. This enhancement resulted from the flow split and recombination induced by the combination of the Coriolis force and grooves. This study will help create and design microchannels for disk chip miniaturization, automation, and integration into lab-on-a-disk-based biomedical procedures, such as point-of-care diagnosis.