Subsecond Codetection of Dopamine and Estradiol at a Modified Sharkfin Waveform

Abstract

17β-Estradiol (E2) is a ubiquitously expressed hormone that is active in a wide range of neuroprotective and regenerative roles throughout the brain. In particular, it is a wellknown dopamine (DA) regulator and is responsible for modulating the expression of dopaminergic receptors and transporters. Recent studies point to E2 release occurring on a rapid time scale and having impacts on DA activity within seconds to minutes. As such, tools capable of monitoring the release of both E2 and DA in real time are essential for developing an accurate understanding of their interactive roles in neurotransmission and regulation. Currently, no analytical techniques capable of codetection of both analytes with high sensitivity, spatiotemporal resolution, extended monitoring, and minimal tissue damage exist. We describe a modified waveform using fast-scan cyclic voltammetry that is capable of low nanomolar detection of both DA and E2 on a subsecond time scale. Both analytes have limits of detection at or below 30 nM and high sensitivity: 11.31 ± 0.55 nA/μM for DA and 9.47 ± 0.36 nA/μM for E2. The waveform is validated in a tissue matrix, confirming its viability for measurement in a biologically relevant setting. This is the first method capable of codetection of fluctuations in DA and E2 with the temporal, spatial, and sensitivity requirements necessary for studying real-time neurochemical signaling.

Waveform Optimization for the In Vitro Detection of Caffeic Acid by Fast-Scan Cyclic Voltammetry

“…After dynamic range testing, stability testing was performed, in a manner consistent with other reports, ,, with the results shown in Figure . Panel 5A shows peak currents, normalized to the first injection, for 32 consecutive FIA measurements of 750 nM caffeic acid, recorded over the course of approximately 1.5 h. There was no significant difference in peak current across the 32 injections (ANOVA P = 0.165, N = 5), and the average relative standard deviation in peak currents across all electrodes was 0.96%.…”

“…Fast-scan cyclic voltammetry (FSCV) is an electroanalytical technique that uses voltage sweeps with scan rates above 100 V/s . An advantage of FSCV over other approaches is that the applied waveform can be applied successively at high frequencies, allowing users to monitor changes in electroactive biomolecules on a subsecond time scale, while maintaining the ability to identify the analyte of interest based on the shapes of the recorded cyclic voltammograms (CV). , Coupled with small-sized biocompatible carbon fiber microelectrodes (CFMs), this technique has been used successfully for over 40 years for the real-time detection of neurochemicals in the living brain, primarily catecholamines. , More recent FSCV advances have included novel waveforms, CFM modifications for enhanced detection capabilities, and an expansion in the types of analytes detected including amino acids, metal ions, metabolites, peptides, hormones, and other small molecules of biochemical significance. − …”

Key Role of Adsorption Site Abundance in the Direct Electrochemical Co-Detection of Estradiol and Dopamine

“…This allowed the evaluation of electrode sensitivity towards both compounds in the same solution. The only other reported codetection study of DA and E2 involved the use of carbon ber microelectrodes and FSCV with a modi ed waveform, enabling subsecond measurements [44].…”

“…However, with the rapid E2 signalling on neurons [41] like DA, the temporal and spatial resolution alongside biocompatibility must be considered for in vivo measurements in the brain [42]. Recently, E2 was characterized using fast-scan cyclic voltammetry (FSCV) [43] and co-detection with DA was achieved with a modi ed waveform [44] which satis ed the temporal and spatial requirements for both compounds.…”