Date of Award
Fall 2025
Project Type
Dissertation
Program or Major
Electrical and Computer Engineering
Degree Name
Doctor of Philosophy
First Advisor
Edward Song
Second Advisor
John LaCourse
Third Advisor
Xuanmao Chen
Abstract
Serotonin, a neurotransmitter and signaling molecule known chemically as 5-hydroxytryptamine (5-HT), holds a pivotal role in orchestrating various physiological and neurological processes within the human body. Its influence extends to regulating mood, cognition, gastrointestinal motility, and other critical functions. Consequently, the precise monitoring of serotonin levels and dynamics is of paramount significance in unraveling its intricate interactions and potential implications for health and disease. Electrochemical serotonin sensing has emerged as a potent and promising tool to enable real-time and continuous monitoring of serotonin, thereby offering unprecedented insights into its complex role in neurophysiology. The neurological significance of serotonin cannot be overstated. As a neurotransmitter, serotonin participates in modulating neuronal communication, influencing mood regulation, emotional responses, and cognitive functions. Furthermore, the gastrointestinal tract, housing a significant portion of the body's serotonin, relies on this molecule to regulate gut motility and peristalsis. Dysregulation of serotonin signaling has been implicated in various neuropsychiatric disorders, such as depression, anxiety, bipolar disorder, and irritable bowel syndrome, underscoring the need for advanced monitoring techniques.
Electrochemical sensing presents a versatile and effective approach for serotonin detection due to its inherent sensitivity, selectivity, and real-time capability. However, the electrochemical detection of serotonin is not devoid of challenges. One major hurdle stems from potential signal interference caused by other electroactive molecules possessing comparable redox potentials. This interference can obscure accurate serotonin measurements, necessitating innovative strategies to enhance the specificity of detection. Aptamer-based electrochemical sensing offers a promising solution to this challenge.
Aptamers, single-stranded DNA or RNA molecules, possess remarkable binding affinity and selectivity for specific target molecules. In the context of serotonin sensing, aptamers can be designed to selectively bind with serotonin molecules, enabling a more precise and reliable detection mechanism. This approach not only circumvents the issue of interference from other electroactive species but also facilitates the creation of biosensors with enhanced sensitivity and specificity. Moreover, aptamer-based electrochemical sensing can be engineered for label-free detection, simplifying the sensing process, and potentially enabling miniaturization for point-of-care applications.
Clinical implications of electrochemical serotonin sensing are profound. The early diagnosis and management of neuropsychiatric disorders heavily rely on accurate biomarker detection. Electrochemical serotonin sensing could offer a non-invasive and rapid means of assessing serotonin imbalances, enabling timely interventions and personalized treatment strategies. Furthermore, this technology holds promise for monitoring the efficacy of pharmacological interventions, aiding clinicians in tailoring dosages and treatment regimens for optimal patient outcomes. The abstract describes the importance of serotonin in health, the benefits of aptamer-based electrochemical sensing and its clinical implications. The electrochemical aptamer-based (E-AB) sensing platform emerges as a versatile and pragmatic method for the direct measurement of specific molecule concentrations, regardless of their chemical reactivity. Notably, this approach is characterized by its swiftness, one-step simplicity, and lack of need for calibration. Using changes in the electrochemical impedance to monitor target binding in proposed electrochemical aptamer based (EAB) sensing platform, initial results show high temporal resolution and stability in measurements performed directly in redox environment. Additional advancements include a methylene blue (MB)-tagged aptamer sensor for improved signal enhancement and a frequency-swept detection approach that improves kinetic resolution and interference rejection. Finally, the sensor was tested in heparinized mouse blood to determine its feasibility in physiologically relevant samples, and it successfully captured serotonin changes in real time.
Recommended Citation
Ahmad, Habib Muhammad Nazir, "CONTINUOUS REAL-TIME MONITORING OF SEROTONIN USING APTAMER-BASED ELECTROCHEMICAL BIOSENSORS" (2025). Doctoral Dissertations. 2955.
https://scholars.unh.edu/dissertation/2955