A Review of Neurotransmitters Sensing Methods for Neuro-Engineering Research

Abstract

Neurotransmitters as electrochemical signaling molecules are essential for proper brain function and their dysfunction is involved in several mental disorders. Therefore, the accurate detection and monitoring of these substances are crucial in brain studies. Neurotransmitters are present in the nervous system at very low concentrations, and they mixed with many other biochemical molecules and minerals, thus making their selective detection and measurement difficult. Although numerous techniques to do so have been proposed in the literature, neurotransmitter monitoring in the brain is still a challenge and the subject of ongoing research. This article reviews the current advances and trends in neurotransmitters detection techniques, including in vivo sampling and imaging techniques, electrochemical and nano-object sensing techniques for in vitro and in vivo detection, as well as spectrometric, analytical and derivatization-based methods mainly used for in vitro research. The document analyzes the strengths and weaknesses of each method, with the aim to offer selection guidelines for neuro-engineering research.

Electrochemical Detection of Neurotransmitters

“…However, NT concentrations in biological samples are relatively low (nM) and therefore require highly sensitive, selective, and reliable biosensors to detect them. Several efforts have been employed to develop transduction mechanisms for the detection of NTs, such as nuclear medicine tomographic imaging (i.e., positron emission tomography and single-photon emission computed tomography), optical sensing (i.e., surface-enhanced Raman spectroscopy, fluorescence, chemiluminescence, optical fiber based biosensors, and colorimetry), analytical chemistry techniques (i.e., high performance liquid chromatography), and microdialysis [10]. These reported techniques require highly trained personnel and are time-consuming, thereby not suitable for point of care testing.…”

Design and Operation of Hybrid Microfluidic Iontronic Probes for Regulated Drug Delivery

“…Evaluating the active delivery—and passive delivery—characteristics of local and low dose delivery devices is generally challenging since many sensing techniques suffer from a high limit of detection. [ 22 ] Here, an enzymatic/amperometric Glu − sensing electrode (Sarissa Biomedical, UK) was used for local, highly sensitive, and real‐time characterization of passive and active delivery of Glu − ( Figure ). When the Glu − electrode sensing tip was positioned 5 mm away from the hybrid probe tip (i), a low amplitude sensing current was measured that we attribute to either intrinsic sensor noise or low concentrations of Glu − passively leaking from the probe (Figure 3b, red trace).…”

Next-Generation Diamond Electrodes for Neurochemical Sensing: Challenges and Opportunities

“…Detection methods for sensing neurochemicals in vivo for the study of neurological disorders would ideally be simultaneously sensitive, minimally-invasive, chronically stable, and relatively inexpensive. In a recent review by S. Niyonambaza et al, techniques for neurotransmitter (NT) identification and quantification were discussed in depth [ 28 ], including positron emission tomography and single photon NT identification and measurement [ 29 , 30 , 31 ], single-photon emission computed tomography [ 32 , 33 ], surface-enhanced Raman spectroscopy [ 34 , 35 ], fast-scan cyclic voltammetry (FSCV) [ 36 , 37 , 38 ], amperometry [ 39 , 40 ], high performance liquid column chromatography (HPLC) [ 41 , 42 , 43 ], fluorescence [ 44 , 45 ], optical fiber sensing [ 46 , 47 ], and colorimetric measurements [ 48 , 49 , 50 ], as seen in Table 1 . Longitudinal positron emission tomography (PET), while non-invasive, is not adequately sensitive to detect subtle changes in dopamine (DA) levels.…”

“…Table based on S. Niyonambaza et al (reproduced from [ 28 ] under a Creative Commons Attribution 4.0 International License).…”