Carbon-Based Quantum Dots for Electrochemical Detection of Monoamine Neurotransmitters—Review

Abstract

Imbalance in the levels of monoamine neurotransmitters have manifested in severe health issues. Electrochemical sensors have been designed for their determination, with good sensitivity recorded. Carbon-based quantum dots have proven to be an important component of electrochemical sensors due to their high conductivity, low cytotoxicity and opto-electronic properties. The quest for more sensitive electrodes with cheaper materials led to the development of electrochemical sensors based on carbon-based quantum dots for the detection of neurotransmitters. The importance of monoamine neurotransmitters (NTs) and the good electrocatalytic activity of carbon and graphene quantum dots (CQDs and GQDs) make the review of the efforts made in the design of such sensors for monoamine NTs of huge necessity. The differences and the similarities between these two quantum dots are highlighted prior to a discussion of their application in electrochemical sensors over the last ten years. Compared to other monoamine NTs, dopamine (DA) was the most studied with GQDs and CQD-based electrochemical sensors.

Metal-Oxide Based Nanomaterials: Synthesis, Characterization and Their Applications in Electrical and Electrochemical Sensors

“…These classes of NTs have a great impact on the smooth running of the central nervous system. Hence, it is very important to precisely quantify NTs in extracellular fluid for an easy diagnosis of health conditions associated with the imbalance in the level of any or all of them in the human body system [ 124 ]. In this case, electrochemical sensors, being characterized by high sensitivity, wide linear range, fast response time and low limit of detection, can be efficiently used for precisely monitoring NTs [ 125 , 126 , 127 ].…”

Metal Nanoparticles and Carbon-Based Nanomaterials for Improved Performances of Electrochemical (Bio)Sensors with Biomedical Applications

“…Due to their unique structure, they present a lot of advantages, such as biocompatibility, nontoxicity, easy functionalization, chemical stability, abundant resources, low cost, versatility, attractive optical properties (photoluminescence), excellent electronic properties, high surface area and good solubility in many solvents [ 193 , 194 , 198 ]. They are widely applied in electrochemical sensing (as signal tags or as electrode modifiers alone or in combination with other nanomaterials), electrochemical flexible devices, electrocatalysis and biofuel cells [ 194 , 198 , 199 , 200 ]. GQDs have been more often used in electrochemical (bio)sensing due to their quantum confinement and edge effect, leading to their higher electrical and thermal conductivity besides their optical properties, as compared to the CDs and traditional quantum dots [ 193 , 197 , 201 ].…”

Simultaneous Electrochemical Sensing of Indole-3-Acetic Acid and Salicylic Acid on Poly(L-Proline) Nanoparticles–Carbon Dots–Multiwalled Carbon Nanotubes Composite-Modified Electrode

“…Carbon dots (CDs) are novel zero-dimensional carbon nanomaterials. Because of their unique fluorescent properties, good biocompatibility and water solubility, small quantum size, low toxicity, and low raw material cost, they have been widely used in many fields, such as medical imaging [ 18 , 19 , 20 ], luminescence detection [ 21 ], electrochemical detection [ 22 ], etc. However, CDs are less attractive in the application of electrochemical sensors as one of their key problems is poor conductivity.…”