Date of Award

2-2022

Degree Name

MS in Electrical Engineering

Department/Program

Electrical Engineering

College

College of Engineering

Advisor

Benjamin Hawkins

Advisor Department

Electrical Engineering

Advisor College

College of Engineering

Abstract

ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY (EIS) has been widely used to study the electrical properties of biological material due to its non-invasive nature and experimental reliability. However, most of the precision impedance analyzers used in EIS only provide single- or two-channel measurements which are inadequate for larger-scale multiplexed measurements, such as those found in modern microfluidic cell culture experiments. The Biomedical Microsystems Laboratory has developed a 16-channel cell culture platform with integrated electrode arrays for monitoring cell growth and electrical properties (i.e., the so-called “electrical phenotype”). In this paper, a system consisting of a 16-channel solid-state analog multiplexer (MUX)paired with a low-cost, impedance analyzer is developed to replace high-cost physical relay MUX and impedance analyzer systems. System requirements and design constraints for monitoring biological systems are considered and a prototype device was fabricated. Initial testing was performed on a breadboard to verify the feasibility of the design idea. Results identified measurement errors due to parasitic elements in the system. Software compensation successfully corrected for parasitic capacitance in the analog MUX design. The accuracy of the measurement system was evaluated on a developed Printed Circuit Board Assembly (PCBA) by comparing theoretical values to MUX compensated data. Finally, an EIS experiment was carried out with tap water with the PCBA system, and measurement results were analyzed using an equivalent Circuit Model (ECM). These results successfully captured the dynamics of charge transport in the electrical double layer, consistent with a modified-Randlecell ECM.

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