Semester of Graduation

Fall 2023


Master of Science in Biological and Agricultural Engineering (MSBAE)


Biological & Agricultural Engineering

Document Type



Flow velocity is a vital parameter for the operation of biomimetic and lab-based microfluidic systems. Optimization of lab-on-a-chip and organ-on-a-chip devices is largely dependent on the precise knowledge of the on-chip fluid velocity. Off-chip sensors which operate on heat transfer and mass transport principles are commonly used, but these sensors lack the capability of real-time on-chip flow characterization. An impedance-based flow sensor containing two coplanar electrodes on a glass substrate is proposed. The sensor’s working principle is based on the electrical double layer theory in which adsorbed ions at the electrode-electrolyte surface are exchanged at a variable rate dependent on flow rate and AC frequency. Microfluidic device fabrication is discussed, and the electrode and microchannel geometries are optimized through rapid prototyping. On-chip velocity is correlated to the measured change in AC resistance, resulting in an impedance-based sensor which can discriminate between flow rates as low as 20 nL/s.



Committee Chair

Monroe, William T.

Available for download on Saturday, August 22, 2026