Waveform Development for Neurotransmitter Detection on Novel Boron-Doped Diamond Microelectrodes

Technologies capable of detecting changes in neurochemical signals can be used to understand the underlying mechanisms of neurological diseases. They are also important components of systems which rely on neurochemical sensing as a source of feedback for closed-loop neuromodulation[1], [2]. Recently, our research team has developed a boron-doped diamond microelectrode (BDDME) fiber for neurotransmitter detection using fast-scan cyclic voltammetry (FSCV). These electrodes have several potential benefits in comparison to more traditional, carbon fiber microelectrodes (CFMEs), including a wider working potential window, customizable fabrication, and increased resistance to etching. Given the unique characteristics of BDDMEs in comparison to CFMEs, there is a need to re-examine and optimize the potential waveforms used for neurotransmitter detection. In this study, we explored waveform parameters (holding potential, scan rate, and application frequency) for serotonin detection on BDDME fibers. We found that frequency attenuation of normalized peak currents was mitigated on BDDMEs in comparison to CFMEs. Effects of varying holding potential and scan rate were qualitatively similar between the two electrode types. Frequency effects suggest that repeating the measurements at BDDME at higher frequency does not decrease the current as drastically as on the CFME. However, both electrodes showed optimal current response at 10 Hz. These studies represent an important step forward in our development of a next-generation, chronically implantable electrochemical sensor for neurotransmitter detection.