Autonomous and complex flow control involving multistep injection and liquid replacement in a reaction chamber on steadily rotating centrifugal microfluidic devices

Abstract

This study demonstrates a novel autonomous flow-control technique using siphon-shaped microchannels on a steadily rotating centrifugal microfluidic device. We also develop a simple microfluidic device, which comprises simple casted polydimethylsiloxane, capable of implementing a multistep, timely flow injection, and the replacement of the liquid present in a chamber, without requiring external triggers to switch the flow operation modes. We demonstrate the multistep, timely flow injection system with the steadily rotating, disk-shaped, microfluidic device and the four steps of flow injection. We investigate the effect of surface tension, which affects the liquid replacement error, on the extent of the remaining liquid plug in a siphon-shaped microchannel to realize a stable liquid replacement. We also investigate the liquid behavior in the siphon-shaped microchannels and develop a suitable design to realize autonomous liquid replacement in the reaction chamber, which is required in automatic chemical processes. Moreover, we develop a device capable of implementing the three-step liquid injection process and the liquid replacement in a liquid reservoir, which are potentially applied with a chemical analysis process, such as the enzyme-linked immunosorbent assay.