Carbon Fiber Microelectrodes Modified with Polymers for Enhanced Neurochemical Detection of Dopamine and Metabolites

While different electrochemical sensors have been introduced over the past thirty years, carbon-fiber microelectrodes (CFMEs) are considered to be the standard electrodes for neurotransmitter detection. Fast-scan cyclic voltammetry (FSCV), an electroanalytical method, primarily uses CFMEs and has the ability to follow neurochemical dynamics in real time. In conjunction with FSCV, CFMEs have the capability to accurately measure the oxidation of several crucial neurotransmitters, like dopamine, to produce specific cyclic voltammograms. Improvements in neurochemical detection with CFMEs were previously made through the coating of polymers onto the surface of the carbon-fiber. Polymers such as PEI, PEDOT, and Nafion were electrodeposited onto the surface of the electrodes to enhance neurochemical detection. This work demonstrates applications for enhancements in co-detection of similarly structured neurochemicals such as dopamine, DOPAL, 3-methoxytyramine, DOPAC, and other neurotransmitters. Manipulating the charge and surface structure of the carbon electrode allows for the improvement of sensitivity and selectivity of neurotransmitter detection. The analytes are detected and differentiated by the shape and the peak positions of their respective cyclic voltammograms. In addition, ex-vivo measurements and qualification of several neurotransmitters in zebrafish brain models are shown.