Electrochemical Detection of Neurotransmitters (original) (raw)
Related papers
2019
It is extremely challenging to chemically diagnose disorders of the brain. There is hence great interest in designing and optimizing tools for direct detection of chemical biomarkers implicated in neurological disorders to improve diagnosis and treatment. Tools that are capable of monitoring brain chemicals, neurotransmitters in particular, need to be biocompatible, perform with high spatiotemporal resolution, and ensure high selectivity and sensitivity. Recent advances in electrochemical methods are addressing these criteria; the resulting devices demonstrate great promise for in vivo neurotransmitter detection. None of these devices are currently used for diagnostic purposes, however these cutting-edge technologies are promising more sensitive, selective, faster, and less invasive measurements. Via this review we highlight significant technical advances and in vivo studies, performed in the last 5 years, that we believe will facilitate the development of diagnostic tools for brain...
Latest Trends in Electrochemical Sensors for Neurotransmitters: A Review
Sensors, 2019
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. Pa...
Clinical chemistry, 1984
Coulometric electrodes in series have been used with liquid chromatography with electrochemical detection to increase selectivity and resolution for the direct analysis of tissue neurotransmitters. Use of three coulometric sensors for electrochemical modification, selectivity, and peak identification has been expanded into "gate" cells of three or four coulometric electrodes that allow elimination of all electrochemically irreversible substances, and "array" cells of up to 15 coulometric electrodes for separation of co-eluting compounds by their current/voltage characteristics. On-column sensitivity of the sensor arrays is 0.4 to 4 pg. Gate cell selectivity favors electrochemically reversible compounds over irreversible ones, e.g., 3-methoxy-4-hydroxyphenylglycol vs ascorbate, by a factor of up to 10(4). Resolution across the multi-electrode array cells allows separation of co-eluting compounds with half-wave potentials differing by as little as 30 to 40 mV. Cell...
Electrochemical Hybrid Biosensors for Neurotransmitters Analysis
2013
Abstrac t Biosensors are devices that detect and transmit information regarding a physiological change or the presence of various chemical or biological materials in a given environment. A new concept of electrochemical biosensors, directly related to the biological redox processes at the cellular and subcellular level, is proposed for testing microfluidic probes, in order to investigate and treat neurological disorders. The micro-electrode features at nanoscale are based on incorporating via electropolymerization of oxidized conductive conjugated polymers at the surface of carbon structures with predefined architectures at nano-scale. The electrochemical characterization of novel micro-electrodes was performed by using reference redox molecules. The final sensorial features regarded the concept sensitivity and reproducibility at different concentrations of dopamine, epinephrine and norepinephrine in acid medium (0.1 M HCl). In order to tailor the hybrid bio-sensors for extended med...
Recent Advances in In Vivo Neurochemical Monitoring
Micromachines
The brain is a complex network that accounts for only 5% of human mass but consumes 20% of our energy. Uncovering the mysteries of the brain’s functions in motion, memory, learning, behavior, and mental health remains a hot but challenging topic. Neurochemicals in the brain, such as neurotransmitters, neuromodulators, gliotransmitters, hormones, and metabolism substrates and products, play vital roles in mediating and modulating normal brain function, and their abnormal release or imbalanced concentrations can cause various diseases, such as epilepsy, Alzheimer’s disease, and Parkinson’s disease. A wide range of techniques have been used to probe the concentrations of neurochemicals under normal, stimulated, diseased, and drug-induced conditions in order to understand the neurochemistry of drug mechanisms and develop diagnostic tools or therapies. Recent advancements in detection methods, device fabrication, and new materials have resulted in the development of neurochemical sensors...
Micromachines
Imbalances in levels of glutamate (GLU) and gamma-aminobutyric acid (GABA) and their sub-second signaling dynamics occur in several brain disorders including traumatic brain injury, epilepsy, and Alzheimer’s disease. The present work reports on the optimization and in vivo testing of a silicon (Si) multifunctional biosensor probe for sub-second simultaneous real-time detection of GLU and GABA. The Si probe features four surface-functionalized platinum ultramicroelectrodes (UMEs) for detection of GLU and GABA, a sentinel site, and integrated microfluidics for in-situ calibration. Optimal enzyme concentrations, size-exclusion phenylenediamine layer and micro spotting conditions were systematically investigated. The measured GLU sensitivity for the GLU and GABA sites were as high as 219 ± 8 nA μM−1 cm−2 (n = 3). The measured GABA sensitivity was as high as 10 ± 1 nA μM−1 cm−2 (n = 3). Baseline recordings (n = 18) in live rats demonstrated a useful probe life of at least 11 days with GL...
Recent Advances in Biosensing for Neurotransmitters and Disease Biomarkers using Microelectrodes
This Minireview focuses on recent advances in the applications of microelectrodes to detect and monitor targeted analytes in bioelectrochemical processes. Notably, these processes are electrochemically driven reactions that involve the detection of targets from the biological realm. Wide-ranging applications of electrochemical sensors have been reported in the last few decades in various research fields, owing to favorable attributes such as high selectivity and sensitivity, rapid analysis, simplicity, easy fabrication, and cost effectiveness. Accordingly, in this Minireview, we explore recent advances in bioelectrochemistry based on small detection probes or structures modified for a variety of analytes, exploiting multi-approach advantages of enhanced electrochemical detection surface or targeted analyte pursuit. The target analytes included in this Minireview are neurotransmitters and disease biomarkers detected using enzymatic and non-enzymatic electrode modifications.
Flexible Electrochemical Transducer Platform for Neurotransmitters
ACS Omega
We have designed a flexible electrochemical transducer film based on PEDOT−titania−poly(dimethylsiloxane) (PTS) for the simultaneous detection of neurotransmitters. PTS films were characterized using various techniques such as transmission electron microscopy, scanning electron microscopy, atomic force microscopy, four probe electrical conductivity, ac-impedance, and thermomechanical stability. The electrocatalytic behavior of the flexible PTS film toward the oxidation of neurotransmitters was investigated using cyclic voltammetry and differential pulse voltammetry. The fabricated transducer measured a limit of detection of 100 nm ± 5 with a response time of 15 s and a sensitivity of 63 μA mM −1 cm −2. The fabricated transducer film demonstrated for the simultaneous determination of epinephrine, dopamine, ascorbic acid, and uric acid with no interference between the analyte molecules. Further, transducer performance is validated by performing with real samples. The results suggested that the fabricated flexible PTS transducer with superior electrocatalytic activity, stability, and low response time can be explored for the sensing of neurotransmitters and hence can be exploited at in vitro and in vivo conditions for the early detection of the various diseases.