Latest Trends in Electrochemical Sensors for Neurotransmitters: A Review

Abstract

Neurotransmitters are endogenous chemical messengers which play an important role in many of the brain functions, abnormal levels being correlated with physical, psychotic and neurodegenerative diseases such as Alzheimer's, Parkinson's, and Huntington's disease. Therefore, their sensitive and robust detection is of great clinical significance. Electrochemical methods have been intensively used in the last decades for neurotransmitter detection, outclassing more complicated analytical techniques such as conventional spectrophotometry, chromatography, fluorescence, flow injection, and capillary electrophoresis. In this manuscript, the most successful and promising electrochemical enzyme-free and enzymatic sensors for neurotransmitter detection are reviewed. Focusing on the activity of worldwide researchers mainly during the last ten years (2010–2019), without pretending to be exhaustive, we present an overview of the progress made in sensing strategies during this time. Particular emphasis is placed on nanostructured-based sensors, which show a substantial improvement of the analytical performances. This review also examines the progress made in biosensors for neurotransmitter measurements in vitro, in vivo and ex vivo.

Electrochemical Aptasensor for Detection of Dopamine

“…The high affinity of aptamer-dopamine binding (KD ≈ 5 nM) was found by the analysis of the binding kinetics. The occurrence of aptamer-dopamine binding was directly confirmed with spectroscopic ellipsometry measurements.Chemosensors 2020, 8, 28 2 of 11 done on the electrochemical detection of dopamine and other neurotransmitters [2,3]. Dopamine can be very easily detected in an aqueous solution by electrochemical methods such as cyclic voltammetry since dopamine undergoes electrochemical oxidation.…”

“…However, a major issue is the selectivity since complex matrices such as blood contain a range of other oxidizable compounds such as urate or ascorbate which would also generate signals, leading to inaccurate readings. Selectivity towards dopamine is therefore required.A wide range of electrode materials have been proposed to increase the selectivity of dopamine detection [2,3]. A few recent examples include the use of materials such as Nafion combined with graphite [4] or multi-walled carbon nanotubes [5] to improve the selectivity towards dopamine.…”

“…Composites of graphene oxide with Bi 2 S 3 nanorods were used for the electrochemical determination of dopamine [13], and arrays of cylindrical gold nanoelectrodes could be used for both the detection of dopamine and for the immobilization and growth of human neural cells [14]. Many other systems based on organic and inorganic materials have been reported for the sensing of dopamine [2,3].Synthetic bio-receptors such as aptamers appeared to be highly attractive for selective detection of dopamine [15][16][17]. Aptamers are artificial, relatively short single strand DNA or RNA oligomers having a particular sequence of nucleotides designed to accommodate a target molecule, e.g., dopamine.…”

“…Chemosensors 2020, 8, 28 2 of 11 done on the electrochemical detection of dopamine and other neurotransmitters [2,3]. Dopamine can be very easily detected in an aqueous solution by electrochemical methods such as cyclic voltammetry since dopamine undergoes electrochemical oxidation.…”

“…A wide range of electrode materials have been proposed to increase the selectivity of dopamine detection [2,3]. A few recent examples include the use of materials such as Nafion combined with graphite [4] or multi-walled carbon nanotubes [5] to improve the selectivity towards dopamine.…”