Fast Cyclic Square-Wave Voltammetry To Enhance Neurotransmitter Selectivity and Sensitivity

Abstract

Although fast-scan cyclic voltammetry (FSCV) has been widely used for in vivo neurochemical detection, the sensitivity and selectivity of the technique can be further improved. In this study, we develop fast cyclic square-wave voltammetry (FCSWV) as a novel voltammetric technique that combines large-amplitude cyclic square-wave voltammetry (CSWV) with background subtraction. A large-amplitude, square-shaped potential was applied to induce cycling through multiple redox reactions within a square pulse to increase sensitivity and selectivity when combined with a twodimensional voltammogram. As a result, FCSWV was significantly more sensitive than FSCV (n = 5 electrodes, two-way ANOVA, p = 0.0002). In addition, FCSWV could differentiate dopamine from other catecholamines (e.g., epinephrine and norepinephrine) and serotonin better than conventional FSCV. With the confirmation that FCSWV did not influence local neuronal activity, despite the large amplitude of the square waveform, it could monitor electrically induced phasic changes in dopamine release in rat striatum before and after injecting nomifensine, a dopamine reuptake inhibitor.

Simultaneous serotonin and dopamine monitoring across timescales by rapid pulse voltammetry with partial least squares regression

“…Multiple cyclic square-wave voltammetry was used to quantify tonic dopamine in vivo with 10-s resolution [56]. Improvements in selectivity and sensitivity were made using fast-cyclic square-wave voltammetry (FCSWV) [57] and N-FCSWV [58] for monitoring dopamine and serotonin in vivo, respectively. Multiplexing has not yet been achieved with squarewavevoltammetry-two different waveforms were needed to measure dopamine [57] vs. serotonin [58].…”

“…Improvements in selectivity and sensitivity were made using fast-cyclic square-wave voltammetry (FCSWV) [57] and N-FCSWV [58] for monitoring dopamine and serotonin in vivo, respectively. Multiplexing has not yet been achieved with squarewavevoltammetry-two different waveforms were needed to measure dopamine [57] vs. serotonin [58]. Additionally, capacitive current simulation, which relies on assumptions about exponential current decay, was needed for background subtraction.…”

Electrochemical characteristics of ultramicro-dimensioned SIROF electrodes for neural stimulation and recording

“…Besides their established use for quantifying neurotransmitter release in in vivo preparations (Wightman et al 1976, Ewing et al 1983, Kovach et al 1984, Oh et al 2018, Park et al 2018, Batton et al 2019, Ultramicro-dimensioned (UM-dimensioned) electrodes have been employed for recording neural activity in vitro (Sekirnjak et al 2006, Yu et al 2012 and in vivo (Schmidt et al 1976, Kozai et al 2012, Deku et al 2018, Gillis et al 2018, and for neural stimulation in vitro (Grumet et al 2000, Stett et al 2000, Jensen et al 2003, Sekirnjak et al 2006 and in vivo (Gillis et al 2018). One potential advantage of using ultramicrodimensioned electrodes for neural stimulation and recording is the possibility of designing multielectrode arrays with small shank dimensions that reduce insertion trauma and the chronic foreign body response (FBR) compared to larger microelectrodes.…”

Recent Advances in In Vivo Neurochemical Monitoring

“…CFMs are the most commonly used electrodes for FSCV applications. Over the years, efforts have been made to change the waveform, scan rate, and electrode materials with the goal of improving FSCV's sensitivity for different neurochemicals [56]. Sensitivity and signal to noise ratio improvements in DA detection were reported by increasing the scan rate from 400 V/s to 2400 V/s [57].…”