Enhancement of fast scan cyclic voltammetry detection of dopamine with tryptophan-modified electrodes

Abstract

Fast scan cyclic voltammetry (FSCV) allows for real-time analysis of phasic neurotransmitter levels. Tryptophan (TRP) is an aromatic amino acid responsible for facilitating electron transfer kinetics in oxidoreductase enzymes. Previous work with TRP-modified electrodes showed increased sensitivity for cyclic voltammetry detection of dopamine (DA) when used with slower scan rates (0.05 V/s). Here, we outline an in vitro proof of concept for TRP-modified electrodes in FSCV detection of DA, and decreased sensitivity for ascorbic acid (AA). TRP-modified electrodes had a limit of detection (LOD) for DA of 2.480 ± 0.343 nM compared to 8.348 ± 0.405 nM for an uncoated electrode. Selectivity for DA/ascorbic acid (AA) was 1.107 ± 0.3643 for uncoated and 15.57 ± 4.184 for TRP-modified electrodes. Additionally, these TRP-modified electrodes demonstrated reproducibility when exposed to extended cycling. TRP-modified electrodes will provide an effective modification to increase sensitivity for DA.

Developmental exposure to the Parkinson’s disease-associated organochlorine pesticide dieldrin alters dopamine neurotransmission in α-synuclein pre-formed fibril (PFF)-injected mice

“…Carbon fiber glass microelectrodes were constructed using a vacuum to pull carbon fiber through a glass capillary tube, pulled using a horizontal electrode puller, broken, and sealed with paraffin ( Ramsson et al , 2015 ). Microelectrodes were cycled for at least 15 min prior to recording at a frequency of 60 Hz, then cycled at 10 Hz until stable ( Davis et al , 2020 ; Ramsson, 2016 ; Ramsson et al , 2015 ; Takmakov et al , 2010 ). Carbon fiber microelectrodes were calibrated using a pipette-based calibration system by adding a dilute stock DA solution to a buffer and measuring the oxidation and/or reduction ( Ramsson, 2016 ).…”

Vitamin C-reduced graphene oxide improves the performance and stability of multimodal neural microelectrodes

“…Table S4 provides an overview of some comparable sensors, demonstrating that the rGO/Au electrodes exhibit comparable or better sensitivity than modified glassy carbon electrodes (GCE) (Wang et al, 2014;Thamilselvan et al, 2019), many carbon fiber electrodes (CFEs) (Davis et al, 2020;Hejazi et al, 2020aHejazi et al, , 2020bPatel et al, 2020), and even modified CNTs (Paloma ¨ki et al, 2018). In contrast to sensitivity, LODs differ greatly among the various electrode types, but importantly, the LOD of the rGO/Au electrodes here is sufficiently low to support their use for the 3), it is also possible to estimate the effective electrochemical surface area of the rGO/Au electrodes, A ESA (Kang et al, 2012;Wang et al, 2014).…”