Progress in electrochemical detection of neurotransmitters using carbon nanotubes/nanocomposite based materials: A chronological review

Neurotransmitters (NTs) are chemical compounds that play an important physiological role in the functioning of central nervous, renal, hormonal, and cardiovascular systems. Their function is to regulate neural interactions by reducing the permeability of gap junctions between adjacent neurons of the same type. The abnormal level may lead to diseases, such as Parkinson's disease, Huntington's disease, Alzheimer's diseases, and other neurological diseases. The devastating health hazards associated with the abnormal presence of NTs in biological systems coupled with the demerits of most modern detection methods necessitates the continuous development of novel electrochemical sensors. Carbon nanotube (CNT)-based sensors, as a result of the large surface area, biocompatibility, and chemical stability supplied by CNTs, have proven to offer massive sensitivity and low limit of detection (LOD). Its significance in sensors applications toward the detection of different group of compounds cannot be overemphasized. There are several review articles on NTs and their determination using different chemically modified electrodes and sensor platform. However, this review highlights the significance of notable NTs and the progress made in the last decade in the design of CNT-based sensors for the detection of common NTs. Secondly, the review intends to highlight some of the challenges associated with the use of CNT-modified electrodes for NT detection, quantification, and in real-life application. Lastly, it will evaluate the future perspective in the use of CNT and its composite modified electrode over other surface modification materials used in sensor fabrication for the determination of NTs.