Date of Award


Degree Name

Master of Science


Biomedical Engineering

First Advisor

Wang, Haibo


This research presents a novel capacitive-sensing-based method to measure fluid velocity for microfluidics devices. To illustrate the importance of fluid velocity measurement, a case study was first conducted for a split and recombine micromixer. The study underscored the influence of fluid velocity on micromixer efficiency and mixing quality. The proposed fluid velocity measurement method employs two capacitance sensing electrodes placed along the fluid channel, capable of detecting small capacitance changes as fluid passing through the sensing area. The relation between capacitance changes and fluid velocity in the proposed sensing structures was developed and hence used to estimate fluid velocity. The proposed technique does not require extensive bench equipment and is suitable for point-of-care applications. To validate our approach, we implemented a two-step 3D printing process, creating a Polylactic acid (PLA) micro platform with embedded graphene–PLA composite electrodes. The accuracy of the developed method was investigated by cross-verifying the obtained velocities with an optical measurement method. Most absolute percentage discrepancies between the results from the proposed method and the optical method are under 12%, validating the precision of the proposed method. Future research will focus on integrating this velocity measurement method into microfluidic devices produced using advanced microfabrication technologies.




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