Real-time Detection Of Dopamine Research Articles

Visual Detection of Dopamine with CdS/ZnS Quantum Dots Bearing by ZIF-8 and Nanofiber Membranes.

Dopamine (DA) is a widely present, calcium cholinergic neurotransmitter in the body, playing important roles in the central nervous system and cardiovascular system. Developing fast and sensitive DA detection methods is of great significance. Fluorescence-based methods have attracted much attention due to their advantages of easy operation, a fast response speed, and high sensitivity. This study prepared hydrophilic and high-performance CdS/ZnS quantum dots (QDs) for DA detection. The waterborne CdS/ZnS QDs were synthesized in one step using the amphiphilic polymer PEI-g-C14, obtained by grafting tetradecane (C14) to polyethyleneimine (PEI), as a template. The polyacrylonitrile nanofiber membrane (PAN-NFM) was prepared by electrospinning (e-spinning), and a metal organic frame (ZIF-8) was deposited in situ on the surface of the PAN-NFM. The CdS/ZnS QDs were loaded onto this substrate (ZIF-8@PAN-NFM). The results showed that after the deposition of ZIF-8, the water contact angle of the hydrophobic PAN-NFM decreased to within 40°. The nanofiber membrane loaded with QDs also exhibited significant changes in fluorescence in the presence of DA at different concentrations, which could be applied as a fast detection method of DA with high sensitivity. Meanwhile, the fluorescence on this PAN-NFM could be visually observed as it transitioned from a blue-green color to colorless, making it suitable for the real-time detection of DA.

Synergetic effect of optimized β-Zn(OH)2/ZnO heterostructure towards electrochemical dopamine detection

In this study, we have synthesized β-Zn(OH)2/ZnO heterostructures via a simple one-pot hydrothermal method followed by calcination at different temperatures under air for electrochemical dopamine (DA) detection. We found that the synergetic effect between optimized β-Zn(OH)2 and ZnO phases in β-Zn(OH)2/ZnO heterostructures boosts electrocatalytic activity. Moreover, β-Zn(OH)2/ZnO heterostructures calcined at 300 °C (i.e.,β-Zn(OH)2/ZnO300) showed enhanced electrochemical activity towards DA oxidation due to its larger electrochemical active surface area and higher adsorption capacity compared to other β-Zn(OH)2/ZnO heterostructures and ZnO. Additionally, β-Zn(OH)2/ZnO300 heterostructures demonstrated remarkable DA selectivity in the presence of over eight biomolecules, achieving rapid detection response in less than 10 seconds with a low detection limit of 0.17 nM and 1.0 nM within a linear range of (1.75–263 nM) and (263–1300 nM), respectively. Moreover, β-Zn(OH)2/ZnO300 heterostructures showed remarkable reproducibility (98.8 %), high stability (98.1 %), and real-time DA detection in human urine samples with a recovery rate ranging from 95.9 % to 103.2 %. Therefore, β-Zn(OH)2/ZnO heterostructures, especially those optimized under 300 °C, possess great potential for electrochemical applications, particularly in DA detection.

Fluorescence sensing probe based on functionalized mesoporous MOFs for non-invasive and detection of dopamine in human fluids

Abnormal amount of dopamine (DA) in human body is closely relate to various diseases, such as Parkinson's disease, pheochromocytoma. Real-time monitoring DA is crucial for disease warning, diagnosis and treatment. Currently, most methods rely on invasive blood testing for detecting DA, which is only completed with the aid of the medical staffs in hospitals. Herein, a non-invasive fluorescence visual strategy is developed for the real-time monitoring DA, based on luminescent nanoparticles and modified mesoporous zeolite imidazole framework (ZIF-8-NH2) dodecahedrons. During the reaction process, DA is enriched through the spatial configuration of ZIF-8-NH2 and hydrogen bonding effect. The luminescence of Cr3+-doped zinc gallate (ZnGa2O4:Cr3+, ZGC) is inhibited by the photo-induced electron transfer (PET) mechanism to realize sensitively detecting DA. The intelligent sensing platform based on the designed fluorescence probe and color recognition system is structured for real-time detection of DA in urine. Furthermore, a skin-fitting hydrogel patch is prepared by combining a fluorescent probe with chitosan, which enables sensitive and accurate detection of DA in sweat without the complex sample pretreatment. The non-invasive fluorescence detection method provides an effective strategy for quantitatively monitoring DA in human fluids.

Aptamer-enhanced organic electrochemical transistors for ultra-sensitive dopamine detection

In this study, we present the development of an ultrasensitive dopamine (DA) aptasensor based on organic electrochemical transistors (OECTs). The aptasensor utilizes a highly efficient DA aptamer immobilized on the surface of a gold gate electrode in the OECT. The functionalization of the aptamer was confirmed through fluorescence intensity measurements and transfer characteristics of the OECT device. Real-time detection of DA was achieved, and the sensor exhibited a linear response in the concentration range of 10 fM to 10 nM, with a detection limit of 10 fM. The aptasensor's working mechanism was elucidated, involving mutual binding between DA and the aptamer that leads to a shift in the transfer characteristics. Our aptasensor shows great promise for sensitive and rapid detection of DA, which is crucial in diagnosing neurological disorders such as Parkinson's and Alzheimer's diseases. The combination of OECTs and aptamer-based recognition elements offers a cost-effective and efficient platform for detecting biomolecules like DA in various clinical applications.

Binary metal oxide (NiO/SnO2) composite with electrochemical bifunction: Detection of neuro transmitting drug and catalysis for hydrogen evolution reaction

The synergetic effect between dual oxides in binary metal oxides (BMO) makes them promising electrode materials for the detection of toxic chemicals, and biological compounds. In addition, the interaction between the cations and anions of diverse metals in BMO tends to create more oxygen vacancies which are beneficial for energy storage devices. However, specifically targeted synthesis of BMO is still arduous. In this work, we prepared a nickel oxide/tin oxide composite (NiO/SnO2) through a simple solvothermal technique. The crystallinity, specific surface area, and morphology were fully characterized. The synthesized BMO is used as a bifunctional electrocatalyst for the electrochemical detection of dopamine (DPA) and for the hydrogen evolution reaction (HER). As expected, the active metals in the NiO/SnO2 composite afforded a higher redox current at a reduced redox potential with a nanomolar level detection limit (4 nm) and excellent selectivity. Moreover, a better recovery rate is achieved in the real-time detection of DPA in human urine and DPA injection solution. Compared to other metal oxides, NiO/SnO2 composite afforded lower overpotential (157 mV @10 mA cm−2), Tafel slope (155 mV dec−1), and long-term durability, with a minimum retention rate. These studies conclude that NiO/SnO2 composite can act as a suitable electrode modifier for electrochemical sensing and the HER.

COF-Coated Microelectrode for Space-Confined Electrochemical Sensing of Dopamine in Parkinson's Disease Model Mouse Brain.

Parkinson's disease (PD) is a progressive neurodegenerative disorder causing the loss of dopaminergic neurons in the substantia nigra and the drastic depletion of dopamine (DA) in the striatum; thus, DA can act as a marker for PD diagnosis and therapeutic evaluation. However, detecting DA in the brain is not easy because of its low concentration and difficulty in sampling. In this work, we report the fabrication of a covalent organic framework (COF)-modified carbon fiber microelectrode (cCFE) that enables the real-time detection of DA in the mouse brain thanks to the outstanding antibiofouling and antichemical fouling ability, excellent analytical selectivity, and sensitivity offered by the COF modification. In particular, the COF can inhibit the polymerization of DA on the electrode (namely, chemical fouling) by spatially confining the molecular conformation and electrochemical oxidation of DA. The cCFE can stably and continuously work in the mouse brain to detect DA and monitor the variation of its concentration. Furthermore, it was combined with levodopa administration to devise a closed-loop feedback mode for PD diagnosis and therapy, in which the cCFE real-time monitors the concentration of DA in the PD model mouse brain to instruct the dose and injection time of levodopa, allowing a customized medication to improve therapeutic efficacy and meanwhile avoid adverse side effects. This work demonstrates the fascinating properties of a COF in fabricating electrochemical sensors for in vivo bioanalysis. We believe that the COF with structural tunability and diversity will offer enormous promise for selective detection of neurotransmitters in the brain.

A Porous Gold-Curcumin Nanocomposite for Picomolar Real-Time Detection of Dopamine in Urine

Engineering nanomaterials for non-invasive electrochemical detection of dopamine (DA) in biological samples has been daunting. We report a novel gold-curcumin (Au-CM) nanocomposite as an electrochemical sensor for real-time ultra-selective detection of DA in urine samples. Gold nanoparticles (∼2–3 nm) encased in porous curcumin (CM) network on the surface of a glassy carbon electrode were synthesized via a galvanostatic method and used as the electrochemical sensor. The modified electrode exhibited excellent sensitivity and selectivity toward DA sensing with a record-low limit of detection (LOD) of 3 pM (signal-to-noise ratio of 3). Our DFT-D3 calculations revealed a higher (by 23.3 kJ mol−1) adsorption energy of DA on the Au-CM nanocomposite than on the bare Au nanocluster. Furthermore, a wide range of detection 1 pM − 400 μM (R 2 = 0.99) was achieved at pH 6. Real-time DA detection was successfully performed in pharmaceutical formulations and urine samples with a single step of dilution with results comparable to clinical values, thus overcoming the complexity of biofluids.

Omnidirectional leaky opto-electrical fiber for optogenetic control of neurons in cell replacement therapy

The pathophysiological progress of Parkinson’s disease leads through degeneration of dopaminergic neurons in the substantia nigra to complete cell death and lack of dopamine in the striatum where it modulates motor functions. Transplantation of dopaminergic stem cell-derived neurons is a possible therapy to restore dopamine levels. We have previously presented multifunctional pyrolytic carbon coated leaky optoelectrical fibers (LOEFs) with laser ablated micro-optical windows (µOWs) as carriers for channelrhodopsin-2 modified optogenetically active neurons for light-induced on-demand dopamine release and amperometric real-time detection. To increase the dopamine release by stimulating a larger neuronal population with light, we present here a novel approach to generate µOWs through laser ablation around the entire circumference of optical fibers to obtain Omni-LOEFs. Cyclic voltammetric characterization of the pyrolytic carbon showed that despite the increased number of µOWs, the electrochemical properties were not deteriorated. Finally, we demonstrate that the current recorded during real-time detection of dopamine upon light-induced stimulation of neurons differentiated on Omni-LOEFs is significantly higher compared to recordings from the same number of cells seeded on LOEFs with µOWs only on one side. Moreover, by varying the cell seeding density, we show that the recorded current is proportional to the dimension of the cell population.

A Fully Integrated and Handheld Electrochemiluminescence Device for Real-Time Detection of Dopamine in Bio-Samples

A Fully Integrated and Handheld Electrochemiluminescence Device for Real-Time Detection of Dopamine in Bio-Samples

Ultra-selective and real-time detection of dopamine using molybdenum disulphide decorated graphene-based electrochemical biosensor

In this work, a graphene-molybdenum disulphide nanocomposite (pGr-MoS2) was synthesized by a hydrothermal method using pulverized graphite (pGr) as the source of graphene, which exhibited ultra-selective electrochemical (EC) sensing towards dopamine (DA) by exhibiting current response only for DA in the presence of biomolecules such as ascorbic acid (AA), uric acid (UA), epinephrine, norepinephrine, folic acid, glucose, nicotine, caffeine, serotonin acetylcholine, glutathione, cysteine, and histidine. A recent work by our group has demonstrated a simultaneous EC sensing of DA, AA, and UA by pGr with selectivity towards DA and was attributed to the less oxidized and intact aromatic structure of pGr, which interacts with the aromatic ring structure of DA. Intriguingly, pGr-MoS2 surpassed the selectivity property of pGr and all the other reported non-enzymatic DA sensors by exhibiting peak only for DA. The limit of detection value (LOD) obtained for DA using pGr-MoS2 was 0.01 nM (i.e., 10 pM) with a linear dynamic range (LDR) from 0.00001 to 10 μM. Thus, the LDR and LOD values satisfactorily meet the sensitivity requirement for detecting DA, which is 1000 magnitudes lower than the normal physiological concentration of DA. A possible mechanism for this superior selectivity of pGr-MoS2 towards DA was proposed and discussed with evidence. Further, the EC sensing was successfully extended to human blood samples spiked with DA, suggesting the efficiency of the sensor to work in real samples.

Sensitivity enhancement in rGO/Mn3O4 hybrid nanocomposites: A modified glassy carbon electrode for the simultaneous detection of dopamine and uric acid

A high sensitive electrochemical sensor was designed for the real time detection of dopamine (DA) and uric acid (UA) by using the Nanocomposite (NC) of reduced graphene oxide nano-octahedral shaped Mn3O4 modified Glassy Carbon Electrode (rGO/Mn3O4/GCE). The effect of Mn3O4 on the electrochemical and physical properties of rGO/Mn3O4 NC by Mn3O4 contents was analyzed by varying the molar ratio of Mn precursor (1, 5 and 10 mM denoted as GM1:1, GM1:5 and GM1:10 respectively). Due to the unique morphology and physical properties originated from Mn3O4, GM1:10/GCE revealed enhanced electrochemical response in terms of large peak potential separation, high selectivity and sensitivity. The GM1:10/GCE displayed a distinct SWV response to DA and UA for 1–600 μM at lowest detection limit of 1.42 μM and 0.76 μM. Additionally, anti-interference property of the designed sensor against electroactive molecules is found to be excellent stability and good reproducibility. Finally, it was make use for the detection of DA and UA in the pharmaceutical compound and physiological residue.

Smartphone-Based Electrochemical Potentiostat Detection System Using PEDOT: PSS/Chitosan/Graphene Modified Screen-Printed Electrodes for Dopamine Detection.

In this work, a smartphone-based electrochemical detection system was designed and developed for rapid and real-time detection of dopamine (DA). The system included a screen-printed electrode (SPE) used as a sensor, a hand-held electrochemical potentiostat and a smart phone with a specially designed app. During the detection period, the SPEs modified with poly(3,4-ethylenedioxythiophene) (PEDOT), chitosan (CS) and graphene (G) were used to convert and amplify the electrochemical reaction signals. The electrochemical potentiostat was used to generate excitation electrical signals and collect the electrical signals converted from the sensor. The smartphone—connected to the detector via Bluetooth-was used to control the detector for tests, further process the uploaded data, and plot graphs in real time. Experimental results showed that the self-designed sensing system could be employed for highly selective detection of DA in the presence of interfering substances such as ascorbic acid (AA) and uric acid (UA). CV was carried out to characterize the electrochemical properties of the modified SPEs and the electrochemical behaviors of DA on the modified SPEs. Finally, according to the analysis of DPV responses of DA, the system could detect DA with a detection sensitivity of 0.52 ± 0.01 μA/μM and a limit of detection of 0.29 μM in the linear range of DA concentrations from 0.05 to 70 μM.

A core-shell molybdenum nanoparticles entrapped f-MWCNTs hybrid nanostructured material based non-enzymatic biosensor for electrochemical detection of dopamine neurotransmitter in biological samples

Dopamine (DA) is a critical neurotransmitter and has been known to be liable for several neurological diseases. Hence, its sensitive and selective detection is essential for the early diagnosis of diseases related to abnormal levels of DA. In this study, we reported novel molybdenum nanoparticles self-supported functionalized multiwalled carbon nanotubes (Mo NPs@f-MWCNTs) based core-shell hybrid nanomaterial with an average diameter of 40–45 nm was found to be the best for electrochemical DA detection. The Mo NPs@f-MWCNTs hybrid material possesses tremendous superiority in the DA sensing is mainly due to the large surface area and numerous electroactive sites. The morphological and structural characteristics of the as-synthesized hybrid nanomaterial were examined by XRD, Raman, FE-SEM, HR-TEM, EDX. The electrochemical characteristics and catalytic behavior of the as-prepared Mo NPs@f-MWCNTs modified screen-printed carbon electrode for the determination of DA were systematically investigated via electrochemical impedance spectroscopy, cyclic voltammetry, and amperometry. The results demonstrate that the developed DA biosensor exhibit a low detection limit of 1.26 nM, excellent linear response of 0.01 µM to 1609 µM with good sensitivity of 4.925 µA µM−1 cm−2. We proposed outstanding appreciable stability sensor was expressed to the real-time detection of DA in the real sample analysis of rat brain, human blood serum, and DA hydrochloride injection.

Facile synthesis of cellulose microfibers supported palladium nanospindles on graphene oxide for selective detection of dopamine in pharmaceutical and biological samples

The cost-effective synthesis of novel functional nanomaterials has received significant attention in the physical and chemical sciences due to their improved surface area, high catalytic activity along with unique morphological features. This paper reports a facile and eco-friendly synthesis of spindle-like palladium nanostructures (PdSPs) on graphene oxide-cellulose microfiber (GO-CMF) composite for the first time. The GO-CMF/PdSPs composite was synthesized by an electrochemical method without the use of additional surfactants and capping agents. The synthesized materials were characterized and confirmed by using transmission electron microscopy, high-resolution scanning electron microscopy, X-ray diffraction spectroscopy, Raman spectroscopy and Fourier-transform infrared spectroscopy. As-synthesized GO-CMF/PdSPs composite modified electrode was used as a selective electrocatalyst for the oxidation of dopamine (DA). The electrochemical redox behaviors of DA were investigated using cyclic voltammetry (CV). The CV results revealed that the GO-CMF/PdSPs composite modified electrode has 10 folds enhanced oxidation current response to DA than GO, PdSPs and GO-CMF modified GCEs. Under optimized conditions, the GO-CMF/PdSPs composite sensor exhibits a linear response to DA in the concentration range from 0.3 to 196.3 μM with the lower detection limit of 23 nM. The nanocomposite electrode also shows promising features towards the reliable and selective detection of DA, which includes high stability, reproducibility and high selectivity towards the commonly interfering species such as ascorbic acid, uric acid, and dihydroxybenzene isomers. The sensor was successfully tested for the real-time detection of DA in the commercial DA injections and human serum samples.

Eco-Friendly Synthesis of Biocompatible Pectin Stabilized Graphene Nanosheets Hydrogel and Their Application for the Simultaneous Electrochemical Determination of Dopamine and Paracetamol in Real Samples

The development of novel and simple active sensing materials is still interested to fabricate a new and improved sensing devices for many industrial, medical and environmental applications. In this work, we have synthesized a new type of pectin (PT) and reduced graphene oxide (RGO) hydrogels (PT/RGO) by using simple sonochemical methods and further used as an active sensing material for simultaneous electrochemical detection of dopamine (DA) and paracetamol (AC). In general, PT and RGO have substantial electrocatalytic activity due to the presence of active functional groups. Herein, the successful formation of PT wrapped RGO was studied by using various analytical techniques. Subsequently, the electrochemical performance of PT/RGO modified glassy carbon electrode (GCE) toward the detection of DA and AC were systematically examined by using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) techniques. As the results, PT/RGO/GCE exhibits the excellent electrochemical activity with a low detection limit (LOD) of 1.5 nM and 1.8 nM, for DA and AC respectively. Especially, the possible mechanism behind the proposed sensor (PT/RGO/GCE) toward detection of DA and AC was clearly scrutinized. In addition, the observed excellent stability, and selectivity of PT/RGO/GCE greater support for the real time detection of DA and AC in human serum and pharmaceutical samples. Thus, the proposed PT/RGO is believed as an exclusive active sensing material with desired properties for future electrochemical sensor applications.

Rapid and Highly Sensitive Detection of Dopamine Using Conjugated Oxaborole-Based Polymer and Glycopolymer Systems.

A conjugated polymer interface consisting of an oxaborole containing polymer and a glycopolymer was used for achieving very high selectivity in dopamine (DA) detection. The optimum binding affinity between the polymers promotes the selectivity to DA through a displacement mechanism while remaining unaffected by other structurally related analogs and saccharide derivatives. Real-time detection of DA with very high selectivity and sensitivity has been demonstrated by immobilizing the polymer conjugates on surface plasmon resonance (SPR) and microcantilever (MCL) sensor platforms. Using the conjugated polymer sensing layer, the SPR biosensor was capable of detecting DA in the concentration range of 1 × 10-9 to 1 × 10-4 mol L-1, whereas the MCL sensor showed a limit of detection (LOD) of 5 × 10-11 mol L-1. We find that the sensing mechanism is based on DA-induced reversible swelling of the conjugated polymer layer and this allows regeneration and reuse of the sensor multiple times. Also, we conclude that SPR is a suitable sensor platform for DA in-line detection at clinical level considering the detection time and stability, whereas MCL can achieve a much lower LOD.

A Microfluidic Chip with Integrated Microelectrodes for Real-time Dopamine Detection

Abstract A microfluidic chip with integrated microelectrodes for real-time dopamine (DA) detection was designed and fabricated. The chip consisted of a polydimethylsiloxane (PDMS) channel plate and a glass electrode plate. One central channel as the culture chamber of neural stem cells and two lateral channels for the transportation of the culture medium were integrated on the PDMS channel plate. Microelectrodes for real-time dopamine detection were integrated on the glass electrode plate. To solve the problem in demoulding the PDMS channel plate from the silicon mold, a novel demoulding method was developed. An Au-Au-Au three-electrode system was constructed, and it performed well in electrochemical detection. The performance of the microfluidic chip was primarily studied by detecting dopamine dissolved in the medium for the culture of neural stem cells. The detection limit of dopamine was 3.92 μM, the linear detection range was from 10 μM to 500 μM, and the detection reproducibility from different chips was less than 4%.

The impact of a parkinsonian lesion on dynamic striatal dopamine transmission depends on nicotinic receptor activation

Dopamine function is disturbed in Parkinson's disease (PD), but whether and how release of dopamine from surviving neurons is altered has long been debated. Nicotinic acetylcholine receptors (nAChRs) on dopamine axons powerfully govern dopamine release and could be critical contributing factors. We revisited whether fundamental properties of dopamine transmission are changed in a parkinsonian brain and tested the potentially profound masking effects of nAChRs. Using real-time detection of dopamine in mouse striatum after a partial 6-hydroxydopamine lesion and under nAChR inhibition, we reveal that dopamine signals show diminished sensitivity to presynaptic activity. This effect manifested as diminished contrast between DA release evoked by the lowest versus highest frequencies. This reduced activity-dependence was underpinned by loss of short-term facilitation of dopamine release, consistent with an increase in release probability (Pr). With nAChRs active, the reduced activity-dependence of dopamine release after a parkinsonian lesion was masked. Consequently, moment-by-moment variation in activity of nAChRs may lead to dynamic co-variation in dopamine signal impairments in PD.