Honors Theses

Date of Award

12-2025

Document Type

Thesis

Department

Biology

First Advisor

Dr. Zulmaris Diaz

Second Advisor

Dr. Rosalynn Vega

Third Advisor

Dr. Cristina Villalobos

Abstract

Noninvasive, wearable biosensors capable of detecting stress biomarkers in sweat require electrodes that are flexible, conductive, insoluble in water, and highly sensitive at low concentrations of analyte. In this work, bovine serum albumin blocked and anti-cmab immobilized nitrogen doped graphene quantum dots integrated polyaniline/polystyrene composite fibermat electrodes (BSA/Anti-Cmab/N-GQDs/PANI/PS electrodes) were synthesized and evaluated as a potential platform for an electrochemical cortisol biosensor in sweat based systems. Polyaniline was utilized in order to provide electrical conductivity, while polystyrene served as a carrying polymer for mechanical support and its hydrophobicity. Composite fibermats were manufactured through Forcespinning™, followed by a secondary polyaniline graft polymerization process to enhance conductivity. Nitrogen doped graphene quantum dots were synthesized through hydrothermal methods and integrated in the fibermat to enhance conductivity as well as additional surface functionality for antibody immobilization. Anti-Cmab antibodies were immobilized onto the fibermat by attaching to NH groups through EDC/NHS coupling. Material characterization was performed at each stage, using Fourier transform infrared spectroscopy to confirm functional groups, ultraviolet visible and fluorescence spectroscopy to evaluate the optical behavior of the quantum dots and nitrogen doping. X-ray diffraction was utilized to examine crystallinity of fibermats. The resulting conductive fibermats demonstrate characteristics suitable for antibody functionalization and biosensing applications in sweat/skin environments, highlighting their potential as flexible and robust electrodes for wearable biosensors.

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Copyright 2025 Ashwin James. All Rights Reserved.

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