Theses and Dissertations

Date of Award

8-1-2025

Document Type

Thesis

Degree Name

Master of Science in Engineering (MSE)

Department

Biomedical Engineering

First Advisor

Nazmul Islam

Second Advisor

Dumitru Caruntu

Third Advisor

Ali Ashraf

Abstract

This research introduces a novel interdigitated gear-shaped graphene-based electrochemical biosensor for the simultaneous detection of dopamine (DA) and cortisol. Modified with graphene–polyaniline (G–PANI) conductive ink, the sensor increased active surface area—94.52% and 57% higher than Metrohm DropSens 110 and circular printed sensors, respectively. Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) Spectroscopy and X-ray diffraction (XRD) were employed for physicochemical characterization. The sensor detects dopamine and cortisol over a linear range of 0.1–100 µM, with limits of detection of 0.043 µM (R² = 0.98) and 0.0577 µg/mL (R² = 0.976), respectively, in phosphate-buffered saline (PBS) using redox probe. Electrochemical performance evaluated using techniques like Cyclic Voltammetry (CV), Differential Pulse Voltammetry (DPV), Electrochemical Impedance Spectroscopy (EIS) and Chronoamperometry, demonstrated high sensitivity, selectivity, and excellent repeatability (RSD of 1.2% for DA and 3.8% for cortisol). Furthermore, the sensor effectively distinguishes dopamine in a ternary mixture containing uric acid (UA) and ascorbic acid (AA) in human serum. The use of laser-induced graphene (LIG) on Kapton film makes the sensor cost-effective and disposable, enhancing its suitability for chronic stress diagnostics and neurological research.

Comments

Copyright 2025 Pritu Parna Sarkar. All Rights Reserved. https://proquest.com/docview/3275322972

Download

Share

COinS