Characterization of a Novel Tubular Carbon Fibre Based Electrode for Dopamine Detection with Fast Scan Cyclic Voltammetry

Abstract: Fast Scan Cyclic Voltammetry (FSCV) is an electrochemical technique, based on ramping a voltage through a microelectrode and measuring the resulting redox current to obtain information about an electroactive molecule. FSCV can be used for the detection of dopamine, which is a vital neurotransmitter. Dopamine is central to conditions such as Parkinson’s disease. The purpose of this thesis was to evaluate if a new type of highly biocompatible microelectrode, called tube electrode, can be used to detect dopamine using FSCV and determine how they compare to standard carbon fibre microelectrodes (CFMEs). In order to achieve this, three main tasks were set and fulfilled. First, a station for in-vitro FSCV was set up and CFMEs of varying sizes were used to detect dopamine at different concentrations. Secondly, the same trials were done with tube electrodes. Finally, the results of the tubes were compared to the CFMEs. In total, four CFMEs and four tube electrodes were investigated. The dopamine concentrations ranged from 20 nM to 40 μM. In short, the results indicate that the tubes generally have lower sensitivity than the CFMEs but better linearity between the increasing dopamine concentration and the resulting current. The tubes also had a marginally higher concentration threshold for dopamine detection. The main challenge encountered was a decrease in sensitivity over time. Here, further investigations are necessary to map the causes responsible. In conclusion, the tube electrodes are able to detect dopamine in-vitro, with concentrations relevant for in-vivo sensing, with a performance comparable to CFMEs. However, further studies are necessary before the tube electrodes can be used for dopamine detection in-vivo.