Characterization of Electroactive Amino Acids with Fast-Scan Cyclic Voltammetry

Author(s):  
Moriah E Weese-Myers ◽  
Ashley E Ross

Abstract Small molecules and signaling peptides are extensively involved in controlling basic brain function. While classical neurotransmitters can be detected with a variety of techniques, methods for measurement of rapidly-released neuropeptides remain underdeveloped. Fast-scan cyclic voltammetry (FSCV) is an electrochemical technique often used for subsecond detection of small molecule neurotransmitters, in vivo. A few peptides have been detected with FSCV; however, a detailed analysis of the electrochemical signature of all electroactive amino acids with FSCV has not been fully investigated. Because the mechanisms, locations, and timescales for signaling peptide release in the brain are relatively unexplored, developing sensitive and selective tools capable of quantitating neuropeptide signaling is essential. To bridge this gap, we used FSCV to characterize the electroactive amino acids: cysteine, methionine, histidine, tryptophan, and tyrosine. We show that tyrosine, tryptophan, and histidine are easily oxidized on carbon fiber surfaces with FSCV, while detection of the sulfur-containing amino acids is more difficult. This study provides critical information for electrochemical waveform design and optimization for detection of peptides containing these amino acids.

The Analyst ◽  
2016 ◽  
Vol 141 (12) ◽  
pp. 3746-3755 ◽  
Author(s):  
Ken T. Wakabayashi ◽  
Michael J. Bruno ◽  
Caroline E. Bass ◽  
Jinwoo Park

Dopamine regulation in the rat brain olfactory tubercle was characterized by fast-scan cyclic voltammetry coupled with carbon–fiber microelectrodes and optogenetics.


Author(s):  
Elisa Castagnola ◽  
Elaine M. Robbins ◽  
Kevin M. Woeppel ◽  
Moriah McGuier ◽  
Asiyeh Golabchi ◽  
...  

Melatonin (MT) has been recently considered an excellent candidate for the treatment of sleep disorders, neural injuries, and neurological diseases. To better investigate the actions of MT in various brain functions, real-time detection of MT concentrations in specific brain regions is much desired. Previously, we have demonstrated detection of exogenously administered MT in anesthetized mouse brain using square wave voltammetry (SWV). Here, for the first time, we show successful detection of exogenous MT in the brain using fast scan cyclic voltammetry (FSCV) on electrochemically pre-activated carbon fiber microelectrodes (CFEs). In vitro evaluation showed the highest sensitivity (28.1 nA/μM) and lowest detection limit (20.2 ± 4.8 nM) ever reported for MT detection at carbon surface. Additionally, an extensive CFE stability and fouling assessment demonstrated that a prolonged CFE pre-conditioning stabilizes the background, in vitro and in vivo, and provides consistent CFE sensitivity over time even in the presence of a high MT concentration. Finally, the stable in vivo background, with minimized CFE fouling, allows us to achieve a drift-free FSCV detection of exogenous administered MT in mouse brain over a period of 3 min, which is significantly longer than the duration limit (usually < 90 s) for traditional in vivo FSCV acquisition. The MT concentration and dynamics measured by FSCV are in good agreement with SWV, while microdialysis further validated the concentration range. These results demonstrated reliable MT detection using FSCV that has the potential to monitor MT in the brain over long periods of time.


Author(s):  
Stefano Vassanelli

Establishing direct communication with the brain through physical interfaces is a fundamental strategy to investigate brain function. Starting with the patch-clamp technique in the seventies, neuroscience has moved from detailed characterization of ionic channels to the analysis of single neurons and, more recently, microcircuits in brain neuronal networks. Development of new biohybrid probes with electrodes for recording and stimulating neurons in the living animal is a natural consequence of this trend. The recent introduction of optogenetic stimulation and advanced high-resolution large-scale electrical recording approaches demonstrates this need. Brain implants for real-time neurophysiology are also opening new avenues for neuroprosthetics to restore brain function after injury or in neurological disorders. This chapter provides an overview on existing and emergent neurophysiology technologies with particular focus on those intended to interface neuronal microcircuits in vivo. Chemical, electrical, and optogenetic-based interfaces are presented, with an analysis of advantages and disadvantages of the different technical approaches.


Signals ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 138-158
Author(s):  
Hsiang-Wei Wang ◽  
Cameron Bringans ◽  
Anthony J. R. Hickey ◽  
John A. Windsor ◽  
Paul A. Kilmartin ◽  
...  

Oxidative stress plays a pivotal role in the pathogenesis of many diseases, but there is no accurate measurement of oxidative stress or antioxidants that has utility in the clinical setting. Cyclic Voltammetry is an electrochemical technique that has been widely used for analyzing redox status in industrial and research settings. It has also recently been applied to assess the antioxidant status of in vivo biological samples. This systematic review identified 38 studies that used cyclic voltammetry to determine the change in antioxidant status in humans and animals. It focusses on the methods for sample preparation, processing and storage, experimental setup and techniques used to identify the antioxidants responsible for the voltammetric peaks. The aim is to provide key information to those intending to use cyclic voltammetry to measure antioxidants in biological samples in a clinical setting.


2019 ◽  
Vol 13 ◽  
Author(s):  
Rachel A. Saylor ◽  
Melinda Hersey ◽  
Alyssa West ◽  
Anna Marie Buchanan ◽  
Shane N. Berger ◽  
...  

2003 ◽  
Vol 77 (4) ◽  
pp. 2768-2774 ◽  
Author(s):  
Bernd Hauck ◽  
Weidong Xiao

ABSTRACT Muscle is an attractive target for gene delivery because of its mass and because vectors can be delivered in a noninvasive fashion. Adeno-associated virus (AAV) has been shown to be effective for muscle-targeted gene transfer. Recent progress in characterization of AAV serotype 1 (AAV1) and AAV6 demonstrated that these two AAV serotypes are far more efficient in transducing muscle than is the traditionally used AAV2. Since all cis elements are identical in these vectors, the potential determinants for their differences in transducing muscle appear to be located within the AAV capsid proteins. In the present study, a series of AAV capsid mutants were generated to identify the major regions affecting AAV transduction efficiency in muscle. Replacement of amino acids 350 to 736 of AAV2 VP1 with the corresponding amino acids from VP1 of AAV1 resulted in a hybrid vector that behaved very similarly to AAV1 in vitro and in vivo in muscle. Characterization of additional mutants carrying smaller regions of the AAV1 VP1 amino acid sequence in the AAV2 capsid protein suggested that amino acids 350 to 430 of VP1 function as a major tissue tropism determinant. Further analysis showed that the heparin binding domain and the major antigenic determinants in the AAV capsid region were not necessary for the efficiency of AAV1 transduction of muscle.


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