A suction-type, pneumatic microfluidic device for liquid transport and mixing

This study presents a new suction-type, pneumatically driven microfluidic device for liquid delivery and mixing. The three major components, including two symmetrical, normally closed micro-valves and a sample transport/mixing unit, are integrated in this device. Liquid samples can be transported by the suction-type sample transport/mixing unit, which comprised a circular air chamber and a fluidic reservoir. Experimental results show that volume flow rates ranging from 50 to 300 mu l/min can be precisely controlled during the sample transportation processes. Moreover, the transport/mixing unit can also be used as a micro-mixer to generate efficient mixing between two reaction chambers by regulating the time-phased deformation of the polydimethylsiloxane (PDMS) membranes. A mixing efficiency as high as 98.4% can be achieved within 5 s utilizing this prototype pneumatic microfluidic device. Consequently, the development of this new suction-type, pneumatic microfluidic device can be a promising tool for further biological applications and for chemical analysis when integrated into a micro-total analysis system (mu-TAS) device.