An integrated microfluidic system for interstitial fluid transdermal extraction

We present a new microfluidic system for transdermal interstitial fluid (ISF) extraction, collection, and volumetric measurement towards the application of continuous glucose monitoring. This device consists of a venturi tube, a volume sensor, pneumatic valves, and microchannels. Under the management of pneumatic valves, demonstration of the defined volume normal saline injection, ISF extraction, collection and volumetric measurement functions of the system is presented using the stable vacuum generated by the integrated venturi structure. The stability of defined volume normal saline injection is tested, and the coefficient of variation for 20 tests is 0.0041. A simulating test of ISF collection and volumetric measurement is done with the system, and the measurement results correlate well (R²=0.9992) with the values measured by micro syringe.