Bubble based microfluidic sensors

A microfluidic sensor using an electrolytic bubble sensing element has been developed and characterized. Impedance measurements in a microfluidic channel are used to monitor the volume changes of an electrolytic bubble. Parameters affecting bubble volume are identified and provide the basis for detection of properties such as pressure, flow rate and chemical content in a microfluidic channel. A finite element simulation illustrates the sensitivity of impedance measurements to bubble volume in a channel. Furthermore, prototype chips of various configurations were fabricated and are presented to illustrate the design considerations for different sensor applications. The sensor was tested and experimental results are presented characterizing its use as a pressure sensor. Results on surface modification experiments give evidence to support the extension of the bubble based sensor to use in chemical detection in microfluidic channels.