Date of Award

Spring 2025

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Program/Concentration

Biomedical Engineering

Committee Director

Gymama Slaughter

Committee Member

Krishnanand Kaipa

Committee Member

Michele Audette

Committee Member

Barbara Hargrave

Abstract

This work presents the development of innovative electrochemical sensors for selective and sensitive dopamine (DA) detection using flexible laser-induced graphene (LIG) electrodes modified with advanced nanocomposites. An LIG electrode synthesized from pyralux film was functionalized with Nb4C3Tx MXene and silver nanoparticles (AgNPs), significantly enhancing its electrochemical performance. The modified electrode exhibited a peak anodic current increase from 150 μA to 330.4 μA and demonstrated a wide linear detection range (100 nM to 10 μM) with a low detection limit of 1 nM and high sensitivity (160.96 μA/nM cm -2). It also displayed excellent selectivity against common interfering compounds, ensuring accurate DA detection. To further improve the electrocatalytic activity of the fabricated sensor, the flexible LIG electrode was integrated with Nb₄C₃Tx MXene, polypyrrole (PPy), and iron nanoparticles (FeNPs). The modification increased the peak anodic current from 43 μA to 104 μA, extending the linear detection range to 1 nM – 1 mM with an ultralow detection limit of 70 pM and a sensitivity of 0.283 μA/nM cm-2. The sensor effectively detected DA in biological samples with high recovery and selectivity, distinguishing it from uric acid, ascorbic acid, glucose, and sodium chloride. The improved LIG-based sensor platform demonstrated exceptional stability, reproducibility, and suitability for real-time DA detection in complex biological matrices. Its flexibility and high performance highlight its potential for advanced biosensing applications, particularly in point-of-care diagnostics.

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DOI

10.25777/dtn7-2n35

ISBN

9798280747173

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