A novel type of a microfluidic system using ferrofluids for an application of μ-TAS

This paper shows the novel type of microfluidic system for the purpose of applications to delivery systems, which is the core device of mu-TAS (micro Total Analysis System) in medicine and biology. The proposed microfluidic control device in this work has been designed for precisely actuating and fast sampling in submicroliter range. Also, the biological liquids have not been contaminated since they have been isolated from the ferrofluids. The magnetic dipoles in ferrofluids line up with the applied field due to the permanent magnet with surface gauss 3400. The maximum net pressure by ferrofluid flows in the rounded microchannel was more than 2 kPa. The device was fabricated by MEMS technology with silicon wafer. The stepping motor with 20 steps was used for the control of delivering the liquids. One step makes the permanent magnet move 18degrees in the circumferential direction and the liquids can be sampled in nanoliter level. This study presents a significant point that a microfluidic delivery system for sampling biological liquids with high pressure in a microchannels can be integrated in mu-TAS.