Micropumps and microfluid components for myTAS applications

In this publication a summary of the research on micropumps and microfluid components for mu mTAS applications is given, which has been conducted in the framework of the research projects VIMAS and MIBIK, supported by the German Ministry of Education, Science, Research and Technology (BMBF). In the framework of VIMAS a mu mTAS for water quality control is developed, which uses four micropumps for the supply of sample, calibrant and carrier solution. For this purpose an electrostatically actuated micropump was developed. This device basically consists of four silicon chips with outer dimensions of 7 x 7 mm2, which are mounted as a stack and form an electrostatic actuation unit and a flap valve unit. Pumping operation is achieved by applying a square wave signal to the electrostatic actuator, which causes an alternate electrostatic attraction and mechanical relaxation of the flexible pump membrane. With a stroke volume of about 30 nl, the actual design delivers a pump rate up to 1 ml/min and a maximum counter pressure of 300 mbar, which is by far sufficient for the operation in a mu mTAS. For fluidic interconnection of the mu mTAS a silicon backplane with total outer dimensions of 30 x 30 mm2 was realized, which comprises anisotropically etched fluid channels on the back side and fluid connection ports on the front side. The fluid channels are closed with an anodically bonded pyrex cover. In the framework of MIBIK two hybrid Flow Injection Analysis (FIA) systems are being developed, which integrate silicon microfluid components with conventional macroscopic fluid devices such as roller pumps. For these analyzers, the following microfluid components have been realized: A micro-miniaturized channel-type immunoreactor; a micro-miniaturized membrane-type immunoreactor; a hybrid-integrated micro-thermostat, and a micro flow-through cell for amperometric biosensors.