A PDMS interstitial fluid transdermal extraction tool

We present a microfluidic based interstitial fluid (ISF) transdermal extraction tool fabricated from polydimethylsiloxane (PDMS), designed towards the application of continuous glucose monitoring. This device consists of a Venturi Tube for vacuum generation, chambers for the introduction of ISF and normal saline solution, pneumatic valves for fluid control, and interconnected microchannels. Vacuum pressure is used for fluid manipulation and a 92 kPa (absolute pressure) vacuum has been achieved, when 220 kPa external pressure is applied to the Venturi Tube. The normally open pneumatic valves are closed under less than 160 kPa operating pressure. Under the control of pneumatic valves, the demonstration of the normal saline injection, ISF extraction and collection function of the tool using the vacuum generated by the Venturi Tube is presented.