Date of Award

Spring 2026

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Electrical & Computer Engineering

Committee Director

Gymama Slaughter

Committee Member

Nancy Xu

Committee Member

Gon Namkoon

Committee Member

Linda Vahala

Abstract

This research focuses on developing a flexible non-enzymatic glucose sensor to address the issues of cost, stability, and limited sensitivity associated with enzymatic glucose sensors. Regular monitoring of glucose levels is required to manage the global health challenge of diabetes. The sensor is built on a cost-effective, durable, flexible, conductive, and high-surface-area substrate acting as a scaffold for modification with easily tunable and electroactive species to enhance glucose detection. The electroactive materials used are zinc oxide (ZnO), palladium (Pd) and platinum (Pt). Laser-induced graphene (LIG) is created by laser engraving. ZnO, Pd and Pt are electrochemically deposited and optimized based on potential, temperature, precursor concentration and electrodeposition duration.

Two sensor designs have been developed. The initial design, Pd/ZnO/LIG, performed well in alkaline medium (0.1 M NaOH), with a sensitivity of 25. 625 µA mM⁻¹ cm⁻² across a broad dynamic range of 2–24 mM and a shelf life of 13 days. The need for physiologically friendly performance necessitated the development of a second design, Pt/ZnO/LIG. It demonstrated significant improvement, particularly excellent performance in phosphate-buffered saline (PBS), a neutral medium. Its sensitivity increased to 37. 125 µA mM⁻¹ cm⁻² within a dynamic range of 0.5–28 mM, excellent stability for over 47 days, with ease of calibration using both cyclic voltammetry (CV) and chronoamperometry (CA) techniques. Additionally, the design exhibited appreciable selectivity for interference species (maltose, fructose, sucrose, dopamine, ascorbic and iii uric acids). Selective membranes (Nafion and Chitosan) are explored to minimize interference effects.

The sensor design was also evaluated for practical feasibility in synthetic urine, where it demonstrated good recovery rates (93–102%). The sensor outperforms other nonenzymatic glucose sensors developed with similar or related materials. This advancement is crucial in enabling continuous glucose monitoring to improve diabetes management.

The Pt/ZnO/LIG performance was also evaluated on a miniaturized potentiostat designed using LM324A operational amplifier (OPA), digital-to-analog converters (DAC), analog-to-digital converters (ADC) and a microcontroller. The performance was benchmarked relative to a commercial Metrohm potentiostat. The outlook in circuitry design should incorporate filters to denoise the signal to enhance glucose monitoring routinely.

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ISBN

9798197813626

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