Carbon Fiber Microelectrodes for Sensitive and Selective Voltametric Detection of Neurochemicals and Neuropeptides

Abstract

Scientific research has established carbon fiber microelectrodes (CFMEs) as powerful instruments that enable high-sensitivity real-time detection of neurochemicals along with neuropeptides. This dissertation investigates the development and optimization of voltammetric methods with CFMEs for improved detection of neurotransmitters including dopamine, serotonin as well as neuropeptide Y (NPY) and glutamate. Due to the challenges encountered in measurement of NPY using conventional waveforms, under in vitro conditions and in vivo conditions, this study employed modified sawhorse waveform (MSW) in combination with fastscan cyclic voltammetry (FSCV) techniques to enhance selectivity and improve signal resolution levels. This technique enabled co-detection of NPY with other catechols such as dopamine, and serotonin. Additionally, glutamate is not electroactive hence making it difficult to measure using conventional electrodes. As a result, we employed enzyme-modified CFME that incorporated glutamate oxidase coated with chitosan. The production of hydrogen peroxide allowed effective measurement of glutamate as well as selective detection among other neurotransmitters such as dopamine and other neurotransmitters. Further, glutamate was detected among other neurotransmitters including dopamine and norepinephrine establishing high selectivity of this technique. The practical aspects of the methods employed were tested in vitro using biological samples. Here we established that NPY could be detected in urine with a sensitivity of 5.8 ± 0.94 nA/μM (n = 5) while glutamate could be detected in both urine and food samples with high selectivity. This study presents combined detection techniques that distinguish between chemically similar neuropeptides and monoamine neurotransmitters which enable distinguishing them in complicated biological settings such as urine. These clinical applications extend to neurological condition diagnosis solutions and therapeutic tracking procedures with specific benefits for Parkinson’s disease and epilepsy as well as depression assessment. Neurotransmitter observation methods that operate at less than one second intervals provide researchers with new opportunities to explore the links between brain operation and actions. The work provides foundational knowledge to develop electrochemical sensors in future through nanomaterial and natural intelligence analysis strategies despite present issues with electrode fouling and interference in signal detection by background noise. The present dissertation promotes CFMEbased sensing technology advancement while supporting its capacity to improve neurochemical analysis applications and enable personalized medicine practices.