Detection Of Dopamine Research Articles

Effect of protein adsorption on hyaluronic acid/curcumin/multi-walled carbon nanotube based electrochemical sensor for detection of dopamine

Resisting protein adsorption on electrode surfaces is one of pivotal challenges in the electrochemical analysis of small bioactive molecules. In this work, we constructed a novel electrochemical sensing electrode modified with hydrophilic hyaluronic acid (HA) and curcumin/multi-walled carbon nanotube (CM/MWCNTs). The modified electrodes were comprehensively characterized for dopamine detection including the sensing sensitivity, selectivity and stability. The constructed electrochemical sensor for dopamine detection exhibited remarkable resistance to protein adsorption because of the inherent hydrophilicity of HA, and synergistically, the superior electrochemical behavior of the CM/MWCNTs composite (quinone/hydroquinone redox couples enabled superior electrochemical behavior). The HA/CM/MWCNTs/GCE performed about 5.0 folds, 3.5 folds and 2.4 folds higher electrocatalytic current for dopamine than that revealed at bare GCE, MWCNTs/GCE, and CM/MWCNTs/GCE, respectively. In addition, the HA/CM/MWCNTs-based sensor demonstrated excellent sensing performance with a low detection limit of 0.009 μM (S/N = 3) within the concentration range from 50 to 200 μM. The constructed HA/CM/MWCNTs-modified glassy carbon electrodes offered a reliable platform for the real-time monitoring of dopamine with no protein absorption.

3D‐Printed Carbon Nanoneedle Electrodes for Dopamine Detection in Drosophila

AbstractIn vivo electrochemistry in small brain regions or synapses requires nanoelectrodes with long straight tips for submicron scale measurements. Nanoelectrodes can be fabricated using a Nanoscribe two‐photon printer, but annealed tips curl if they are long and thin. We propose a new pulling‐force strategy to fabricate a straight carbon nanoneedle structure. A micron‐width bridge is printed between two blocks. The annealed structure shrinks during pyrolysis, and the blocks create a pulling force to form a long, thin, and straight carbon bridge. Parameterization study and COMSOL modeling indicate changes in the block size, bridge size and length affect the pulling force and bridge shrinkage. Electrodes were printed on niobium wires, insulated with aluminum oxide, and the bridge cut with focused ion beam (FIB) to expose the nanoneedle tip. Annealed needle diameters ranged from 400 nm to 5.25 μm and length varied from 50.5 μm to 146 μm. The electrochemical properties are similar to glassy carbon, with good performance for dopamine detection with fast‐scan cyclic voltammetry. Nanoelectrodes enable biological applications, such as dopamine detection in a specific Drosophila brain region. Long and thin nanoneedles are generally useful for other applications such as cellular sensing, drug delivery, or gas sensing.

3D-Printed Carbon Nanoneedle Electrodes for Dopamine Detection in Drosophila.

In vivo electrochemistry in small brain regions or synapses requires nanoelectrodes with long straight tips for submicron scale measurements. Nanoelectrodes can be fabricated using a Nanoscribe two-photon printer, but annealed tips curl if they are long and thin. We propose a new pulling-force strategy to fabricate a straight carbon nanoneedle structure. A micron-width bridge is printed between two blocks. The annealed structure shrinks during pyrolysis, and the blocks create a pulling force to form a long, thin, and straight carbon bridge. Parameterization study and COMSOL modeling indicate changes in the block size, bridge size and length affect the pulling force and bridge shrinkage. Electrodes were printed on niobium wires, insulated with aluminum oxide, and the bridge cut with focused ion beam (FIB) to expose the nanoneedle tip. Annealed needle diameters ranged from 400 nm to 5.25 μm and length varied from 50.5 μm to 146 μm. The electrochemical properties are similar to glassy carbon, with good performance for dopamine detection with fast-scan cyclic voltammetry. Nanoelectrodes enable biological applications, such as dopamine detection in a specific Drosophila brain region. Long and thin nanoneedles are generally useful for other applications such as cellular sensing, drug delivery, or gas sensing.

The potential of a novel enzyme-based surface plasmon resonance biosensor for direct detection of dopamine

Dopamine is one of the significant neurotransmitters and its monitoring in biological fluids is a critical issue in healthcare and modern biomedical technology. Here, we have developed a dopamine biosensor based on surface plasmon resonance (SPR). For this purpose, the carboxymethyl dextran SPR chip was used as a surface to immobilize laccase as a bioaffinity recognition element. Data analysis exhibited that the acidic pH value is the optimal condition for dopamine interaction. Calculated kinetic affinity (KD) (48,545 nM), obtained from a molecular docking study, showed strong association of dopamine with the active site of laccase. The biosensor exhibited a linearity from 0.01 to 189 μg/ml and a lower detection limit of 0.1 ng/ml (signal-to-noise ratio (S/N) = 3) that is significantly higher than the most direct dopamine detecting sensors reported so far. Experiments for specificity in the presence of compounds that can co-exist with dopamine detection such as ascorbic acid, urea and l-dopa showed no significant interference. The current dopamine biosensor with high sensitivity and specificity, represent a novel detection tool that offers a label-free, simple procedure and cost effective monitoring system.

Development of ATP-modified CoFe2O4@ZIF-8@ZIF-67 core–shell nanozyme for sensitive colorimetric detection of dopamine

Core-shell nanostructures (NSs) are a type of nanozyme broadly used in various fields due to their significant physicochemical advantages. In the present study, the CoFe2O4@ZIF-8@ZIF-67 core–shell were fabricated by a consecutive two-step synthesis method, including hydrothermal for CoFe2O4 metal spinel and epitaxial solvothermal growth of ZIFs bilayers on the metal spinel NSs. The core–shell surface was modified using ATP inspired by the active site of the natural peroxidase enzyme. The nanocomposites were characterized by XRD, FT-IR, SEM, EDX, and Dot-mapping techniques. The peroxidase-like activity of the ATP/CoFe2O4@ZIF-8@ZIF-67 was assessed by a colorimetric method. Modified nanocomposite displayed desirable peroxidase mimetic activity and could enzymatically generate hydroxyl radicals from H2O2 and oxidize TMB. The high catalytic activity of ATP-modified nanocomposite and its ability to oxidize TMB provides a rapid and sensitive platform for the colorimetric detection of dopamine. Dopamine consumes hydroxyl radicals, prevents TMB oxidation, and causes a color change in the detection solution, which the naked eye can recognize. The presented colorimetric test provided an excellent LOD for dopamine (0.4 µM) with a good linear range (0.2–18 µM) and selectivity, which was prosperously applied to dopamine assay in serum blood samples.

A Dopamine Detection Sensor Based on Au-Decorated NiS2 and Its Medical Application.

This article reports a simple hydrothermal method for synthesizing nickel disulfide (NiS2) on the surface of fluorine-doped tin oxide (FTO) glass, followed by the deposition of 5 nm Au nanoparticles on the electrode surface by physical vapor deposition. This process ensures the uniform distribution of Au nanoparticles on the NiS2 surface to enhance its conductivity. Finally, an Au@NiS2-FTO electrochemical biosensor is obtained for the detection of dopamine (DA). The composite material is characterized using transmission electron microscopy (TEM), UV-Vis spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The electrochemical properties of the sensor are investigated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and time current curves in a 0.1 M PBS solution (pH = 7.3). In the detection of DA, Au@NiS2-FTO exhibits a wide linear detection range (0.1~1000 μM), low detection limit (1 nM), and fast response time (0.1 s). After the addition of interfering substances, such as glucose, L-ascorbic acid, uric acid, CaCl2, NaCl, and KCl, the electrode potential remains relatively unchanged, demonstrating its strong anti-interference capability. It also demonstrates strong sensitivity and reproducibility. The obtained Au@NiS2-FTO provides a simple and easy-to-operate example for constructing nanometer catalysts with enzyme-like properties. These results provide a promising method utilizing Au coating to enhance the conductivity of transition metal sulfides.

Ti3C2Tx Coated with TiO2 Nanosheets for the Simultaneous Detection of Ascorbic Acid, Dopamine and Uric Acid.

Two-dimensional MXenes have become an important material for electrochemical sensing of biomolecules due to their excellent electric properties, large surface area and hydrophilicity. However, the simultaneous detection of multiple biomolecules using MXene-based electrodes is still a challenge. Here, a simple solvothermal process was used to synthesis the Ti3C2Tx coated with TiO2 nanosheets (Ti3C2Tx@TiO2 NSs). The surface modification of TiO2 NSs on Ti3C2Tx can effectively reduce the self-accumulation of Ti3C2Tx and improve stability. Glassy carbon electrode was modified by Ti3C2Tx@TiO2 NSs (Ti3C2Tx@TiO2 NSs/GCE) and was able simultaneously to detect dopamine (DA), ascorbic acid (AA) and uric acid (UA). Under concentrations ranging from 200 to 1000 μM, 40 to 300 μM and 50 to 400 μM, the limit of detection (LOD) is 2.91 μM, 0.19 μM and 0.25 μM for AA, DA and UA, respectively. Furthermore, Ti3C2Tx@TiO2 NSs/GCE demonstrated remarkable stability and reliable reproducibility for the detection of AA/DA/UA.

Fabrication of ternary hybrid composites of Co-MOFs/MoS2/PEDOTs for sensitive detection of dopamine and norepinephrine in biological samples

In this study, a simple and multifunctional application for Co-based organic frameworks (Co-MOFs) with molybdenum disulfide (MoS2) and poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOTs:PSS) is presented. The Co-MOFs with MoS2 exhibit excellent peroxidase mimicking and catalytic activities, making them suitable for colorimetric dopamine sensors. From an electrochemical standpoint, fouling-free and selective sensing of dopamine (DA) and norepinephrine (NE) is highly challenging. However, the synergistic effect of morphological tunability of Co-MOFs with hybrid composites of MoS2 and PEDOTs:PSS offers a wide detection concentration range of 2 nM-350 µM for DA and 20 nM-1000 µM for NE, high sensitivity, excellent anti-fouling, facile kinetic rate reaction, and rapid signal response. A high selectivity rate was achieved in the presence of twenty times higher concentrations of a mixture of ascorbic acid, uric acid, and other bio-chemical co-interferents. Interestingly, ultrasensitive detection limits of 0.23 nM and 2.18 nM (S/N = 3) were achieved for DA and NE, enabling the real-time precise detection of cellular concentrations in PC12 living cells, and biological fluid samples with simple dilution pretreatments. Moreover, the sensor demonstrated satisfactory reproducibility and stability. Finally, the morphological and composite activity-based probes can detect neurotransmitter concentrations in real samples beyond the concentration limit, suggesting a potential clinical sensor tool.

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.

Ultrasensitive composite electrochemical sensor with printed wrinkled CNTs nanostructure for simultaneous detection

Combining biomimetic and 3D printing has created new opportunities for the manufacture of electrochemical sensors. Dopamine (DA) and Uric acid (UA) are common body electroactive substances, and their detection is important for diagnosing metabolic diseases. Metal electrochemical sensors have limitations in sensitivity and selectivity due to their smooth 2D structures, which make it challenging to capture comprehensive electrochemical information. Here, inspired by taste buds, an ultrasensitive CNT-Pt composite electrochemical sensor, including a printed biomimetic wrinkled CNTs film, was prepared for simultaneous detection of DA and UA. Nanoscale Pt electrode was prepared by UV-LIGA process and the wrinkled CNTs nanofilm was fabricated by thermally assisted electrohydrodynamic jet (E-Jet) printing. CNT lines of 3∼58 μm, droplets of 4 μm and 2D array structures have been printed. The enhanced sensing mechanism of wrinkled CNTs nanofilm was analyzed theoretically. The nanoscale wrinkled morphology (nanofolds∼50 nm) and hydrophilicity (CÃ20°) of printed wrinkled CNTs nanofilm were analyzed. The anodic peak potential for UA was observed to range from 0.429 V to 0.489 V for the conventional Pt electrochemical sensor, whereas it ranged from 0.205 V to 0.276 V for the CNT-Pt composite electrochemical sensor. The detection performance of CNT-Pt composite electrochemical sensor was improved by ∼40 % contrast with Pt electrochemical sensor. The prepared composite electrochemical sensor can effectively recognize DA, UA and AA. From analysis, the peak value of AA was not obvious, the peak values of DA and UA were 0.096 V and 0.265 V. The composite electrochemical sensor successfully eliminated the detection interference caused by AA in detecting DA and UA. The nanoscale composite electrochemical sensor and its hybrid manufacturing method provide great potential for electrochemical testing applications.

The construction of peroxidase-like Cu-BDC@FeMo6 for colorimetric detection of H2O2 and dopamine

Artificial mimic enzymes have attracted wide attention for their superior characteristics to natural enzymes in extensive applications of diagnosis and therapy. In this paper, a nanozyme Cu-BDC@FeMo6 was designed and fabricated by embedding polyoxometalate (NH4)3[FeMo6O18(OH)6]·6H2O (FeMo6) into a copper-based metal–organic framework (Cu-BDC). The integration of FeMo6 and Cu MOF based on the synergies of oxidability of FeMo6 and oxygen-driven reversible Cu+/Cu2+ enhanced the peroxidase mimicking activity, which accomplished the sensitive visual monitoring of H2O2 and dopamine (DA). The detection of H2O2 was driven by Cu-BDC@FeMo6 catalyzing the oxidation of TMB with colorimetric evolution to blue, and consecutive monitoring DA via the reverse process of reduction of ox-TMB was further achieved. The limit of detection (LOD) of H2O2 and DA were 10 μM and 2.27 μM, with excellent stability, and outstanding selectivity. The mechanism of the catalysis was further evaluated, and the generation of O2·- played a crucial role in the catalysis for oxidation. The logic gate design was constructed to illustrate the process and application. This work provides a feasible reference for the reasonable design of simulated enzyme in biosensor applications.

Simultaneous electrochemical detection of ascorbic acid, dopamine and uric acid using Au decorated carbon nanofibers modified screen printed electrode

Simultaneous electrochemical detection of ascorbic acid, dopamine and uric acid using Au decorated carbon nanofibers modified screen printed electrode

Computational simulation and fabrication of a simple, rapid and sensitive dopamine electrochemical sensor based on recycled biomass

Dopamine addiction brought on by recreational or misuse can result in neurological issues that have significant societal and economic consequences. Thus, a precise, sensitive, and rapid method for measuring dopamine is necessary for monitoring treatment and forensic investigations. In this research, an electrochemical sensor based on recycled biomass was fabricated for the sensitive detection of dopamine. The synthesised recycled nanocomposite was characterised by energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). A computational simulation of the materials was carried out to predict the potential of the composite. A DFT was used to obtain a global hardness value of 0.28 eV, indicating the chemical reactiveness and its easy activation for adsorption, as supported by the energy gap value of 0.57 eV. Adsorption in water, solvent, ΔH, ΔS, and ΔG exhibits thermodynamic parameters of -2.89 kCal/mol, -72.97 Cal/mol/K, and 18.86 kCal/mol, indicating more ordered endergonic and exothermic processes. Electrochemical investigations using DPV and CV revealed a limit of detection (LOD) of 0.003 μM. The potential utility of the modified electrode was assessed in human urine, serum, and saliva. The research showed the possible applicability of the sensor for forensic, diagnostic, and quality control purposes.

Highly sensitive and selective detection of dopamine using atomic layer deposited HfO2 ultra-thin films

The development of non-enzymatic and binder-free biosensors plays a vital role, and it possesses main benefits for effective biomolecule recognition with high sensitivity and preferred selectivity. Herein, an atomic layer deposition (ALD) was employed to develop the hafnium oxide (HfO2) nanofilm on silicon (Si) for fabricating binder-free selective and sensitive determination of the non-enzymatic electrochemical dopamine sensor. The prepared HfO2 nanofilm selectively acted as a local dopamine binding site because of the hydrophobic-hydrophobic interaction between fabricated film and dopamine, electrostatic attraction between negatively charged hydroxyl group on film surfaces, and positively charged amino group of dopamine. The developed insufficient oxygen vacancies on the HfO2 could have behaved as a charge-trapping site for better sensing properties. The developed sensor demonstrated excellent realization in sensing dopamine with a very low detection limit (0.4 pM) and swift response time of 3s which is quite precise compared with various reported literature. The fabricated HfO2/Si electrode sensor has exhibited high sensitivity, stability, and repeatability. The selectivity of dopamine sensors was at least three orders greater than other interfering biomolecules. This work proposes the essential track for the practical realization of dopamine detection in human serum and biomedical applications.

Oxygen-deficiency induced fluorescence nanosensor (ODIFN): Synthesis of Two-Dimensional NayWO4-x·2H2O nanosheets and its application in dopamine detection

Oxygen-deficiency induced fluorescence nanosensor (ODIFN) method applied in the Two-Dimensional nanosheets has been demonstrated in this paper. In this approach, we synthesized the abundant oxygen-deficient Two-Dimensional (2D) NayWO4-x·2H2O nanosheets fluorescence sensors and applied them for highly sensitive and selective dopamine detection. Researchers have been intensively motivated to create novel nanomaterials that enable the effective detection of dopamine (DA) in clinical samples. DA is a significant biomarker for various brain-related diseases such as Parkinson’s disease. We developed 2D NayWO4-x·2H2O nanosheets that exhibited a stable fluorescence emission at λem 360 nm. The non-stochiometric Na presenting in 2D nanosheets acts as a defecting agent for oxygen deficiency that results in strong and stable fluorescence. The fabricated fluorescence nanosheets were exhibited for the detection of dopamine with high sensitivity and selectivity. The ODIFN demonstrated a linear range of detection from 50 nM to 2 µM with a limit of detection of 0.31 nM and a very high R2 value of 0.996. Moreover, the sensor performance was evaluated in a biological fluid (blood serum) with results of R2 value of 0.995, which proves the high potential of NayWO4-x·2H2O nanosheets in DA sensing. The ODIFN via the 2D NayWO4-x·2H2O fluorescent sensor is a novel platform for producing artificial fluorescence that can be widely applied in all fields such as medical, biological, and life science fields to replace the traditional dyes that are highly harmful to environments.

Fabrication of nickel aluminate based electrochemical sensor for dopamine detection

Nickel aluminate nanoparticles (NiAl2O4 NPs) spinel structure is synthesized via a simple solution combustion method using aqueous nickel nitrate, aluminum nitrate and citric acid. The crystal structure and microstructure of the prepared NiAl2O4 NPs are confirmed by powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectrum, scanning and transmission electron microscopy (SEM/TEM). The characterized NiAl2O4 NPs are applied on a glassy carbon electrode (GCE) to design electrochemical sensor for the detection of dopamine (DA) using cyclic voltammograms (CV) and differential pulse anodic stripping voltammograms. The proposed electrochemical sensor exhibits excellent sensing activity with a low detection limit of 1.78 μM and applicable for a wide linear concentration range of 10 μM–140 μM. Further, the proposed electrode exhibits well resolved differential pulse voltammogram for the dopamine in presence of interfering uric acid and ascorbic acid.

Interfacially Ordered NiCoMoS Nanosheets Arrays on Hierarchical Ti3C2Tx MXene for High‐energy‐density Fiber‐Shaped Supercapacitors with Accelerated Pseudocapacitive Kinetics

Balancing electrochemical activity and structural reversibility of fibrous electrodes with accelerated Faradaic charge transfer kinetics and pseudocapacitive storage are highly crucial for fiber‐shaped supercapacitors (FSCs). Herein, we report novel core‐shell hierarchical fibers for high‐performance FSCs, in which the ordered NiCoMoS nanosheets arrays are chemically anchored on Ti3C2Tx fiber. Beneficial from architecting stable polymetallic sulfide arrays and conductive networks, the NiCoMoS‐Ti3C2Tx fiber maintains fast charge transfer, low diffusion and OH‐ adsorption barrier, and stabilized multi‐electronic reaction kinetics of polymetallic sulfide. Consequently, the NiCoMoS‐Ti3C2Tx fiber exhibits a large volumetric capacitance (2472.3 F cm‐3) and reversible cycling performance (20,000 cycles). In addition, the solid‐state symmetric FSCs deliver a high energy density of 50.6 mWh cm‐3 and bending stability, which can significantly power electronic devices and offer sensitive detection for dopamine.

Electrochemically Grown Hole-Rich NiO(OH) Thin Films toward Hole-Mediated Very Fast and Selective Enzyme-Free Electrochemical Sensing of Dopamine under Simulated Environment.

This work aimed to develop an enzyme-free semiconductor-assisted electrochemical technique for the selective detection of the neurotransmitter dopamine. In this case, electrochemically grown nickel oxyhydroxide [NiO(OH)] thin films were chosen to fabricate the sensing platform, i.e., the electrodes. Chronoamperometry was used to deposit the films on indium tin oxide (ITO) coated glass substrates. The films were thoroughly characterized to establish their structure, composition, phase purity, and electrochemical attributes. Electrochemical sensing characteristics were investigated by means of cyclic and differential pulse voltammetry, steady-state amperometry, and electrochemical impedance spectroscopy. The effects of several interfering agents like glucose, sodium chloride, methanol, hydrogen peroxide, and paracetamol were also studied on the detection attributes of dopamine. Significantly high value of sensitivity (11.87 μA μM-1 cm-2) was obtained for dopamine sensing that was associated with a limit of detection (LoD) of 0.22 μM of dopamine. However, the sensitivity (2.51 μA μM-1 cm-2) and LoD (1.20 μM) obtained for serotonin were inferior compared to those of dopamine. The performance of the electrode toward dopamine sensing was not compromised either in the presence of only serotonin or a series of other electroactive interfering agents, which makes the electrode very much dopamine selective. The dopamine response time was 200 ms, which is notably fast. Extensive studies on the effect of temperature, pH and scan rate on the detection of dopamine by the developed electrode material have also been carried out. The developed electrodes were also found to be notably stable for dopamine detection with a decay of only 6.6% in oxidation peak current density after the 50th cycle. Real-life application of the developed electrode material was checked with urine samples from adult male humans and yielded encouraging results.

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.

Development of An Eco-Friendly and Cost-Effective Electrochemical Sensor for the Simultaneous Detection of Dopamine and Serotonin

An electrochemical sensor based on eco-friendly green synthesized silver nanoparticles decorated reduced graphene oxide (AgNPs-rGO) modified screen-printed carbon electrode (SPCE) for the simultaneous detection of serotonin (5-HT) and dopamine (DA) is reported for the first time. The experimental parameters affecting the sensor performance were optimized in terms of AgNPs-rGO coating amount, scan rate and electrolyte pH (6–8). Under optimal conditions, the AgNPs-rGO/SPCE was employed to individually determine both analytes using DPV technique. The sensor was also efficient in the simultaneous detection of these species and reported well-resolved oxidation peaks with a linear range of 10–100 μM and detection limits of 7 μM and 7.41 μM, respectively. The developed device showed good selectivity, reproducibility, and repeatability. Furthermore, it was successfully applied to the determination of both biomolecules in artificial urine samples with good recovery. The main advantages of the designed sensor are its simplicity, portability, and low cost.