An electrochemical-based thermal flow sensor

The first thermal flow sensor to operate on the principle of measuring thermal changes in ionic mobility vis-à-vis electrochemical impedance resulting from flow was developed and demonstrated. Its biocompatible construction on a flexible polymer substrate enables unobtrusive integration with medical implants such as shunts and catheters. Flow is transduced by utilizing electrochemical impedance measurements between an electrode pair to detect temperature changes resulting from transport of liquid focally heated upstream. This approach offers increased sensitivity compared to solid sensing materials and compatibility in saline environments. Flow rates below 320 μL/min could be detected with a limit of detection of 10.7 μL/min. The simple design and performance range is suitable for in vivo applications.