Carbon Nanotube-based microelectrodes for enhanced detection of neurotransmitters

Fast-scan cyclic voltammetry FSCV is one of the common techniques used for rapid measurement of neurotransmitters in vivo Carbon-fiber microelectrodes CFMEs are typically used for neurotransmitter detection because of sub-second measurement capabilities ability to measure changes in neurotransmitter concentration during neurotransmission and the small size electrode diameter which limits the amount of damage caused to tissue Cylinder CFMEs typically    m long are commonly used for in vivo experiments because the electrode sensitivity is directly related to the electrode surface area (owever the length of the electrode can limit the spatial resolution of neurotransmitter detection which can restrict experiments in Drosophila and other small model systems )n addition the electrode sensitivity toward dopamine and serotonin detection drops significantly for measurements at rates faster than  (z limiting the temporal resolution of CFMEs While the use of FSCV at carbon-fiber microelectrodes has led to substantial strides in our understanding of neurotransmission techniques that expand the capabilities of CFMEs are crucial to fully maximize the potential uses of FSCV This dissertation introduces new methods to integrate carbon nanotubes CNT into microelectrodes and discusses the electrochemical enhancements of these CNTmicroelectrodes The electrodes are specifically designed with simple fabrication procedures so that highly specialized equipment is not necessary and they utilize Jacobs ii commercially available materials so that the electrodes could be easily integrated into existing systems The electrochemical properties of CNT modified CFMEs are characterized using FSCV and the effect of CNT functionalization on these properties is explored in Chapter  For example CFME modification using carboxylic acid functionalized CNTs yield about a -fold increase in dopamine oxidation current but modification with octadecylamine CNTs results in a negligible change to the signal Chapter  is devoted to the development and characterization of new CNT-Yarn Microelectrodes CNTYME which display a beneficial enhancement in sensitivity and reduction in both electron transfer kinetics and overpotential Chapter  introduces the highspeed dopamine detection capabilities of CNTYMEs almost two orders of magnitude faster than at CFMEs without any compromise in electrochemical sensitivity and discusses how adsorption and desorption relate to this phenomenon

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