Selective Detection Of Dopamine Research Articles

Ultrafast and selective detection of dopamine by DC sputtered highly oriented CuO thin films: Effect of electroactive interfering agents and temperature

Dopamine and serotonin are two neurotransmitters that play critical role in human physiology. In this work, it has been aimed to synthesize a chip-based sensing platform that can detect dopamine precisely in a non-enzymatic way in presence of a series of electroactive interfering agents. Copper oxide (CuO), a p-type material with excellent surface and electrochemical properties, has been deposited through direct current (DC) sputtering technique on indium doped tin oxide (ITO) coated glass substrates as the sensing platform. The structure, phase purity and other essential properties of the modified electrode were established through x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR) and ultraviolet – visible (UV–Vis) spectroscopy. Detailed electrochemical investigations with the modified electrode have also been carried out using cyclic voltammetry (CV), chronoamperometry (i – t) and electrochemical impedance spectroscopy (EIS) that revealed ultrafast response (10 ms), excellent sensitivity (5.41 µAµM-1cm−2) and low limit of detection (LoD) of 0.46 µM for the electrode towards dopamine. The electrode exhibited sensitivity of 0.37 µAµM-1cm−2 with average LoD of 19.2 µM towards serotonin, which is inferior to dopamine. The threshold response potential was also quite different for dopamine and serotonin. The modified electrode was also found to be nonresponsive to a series of electroactive interfering agents, making it dopamine selective. The role of p-type conductivity of the electrode material towards such selective detection of dopamine was also explained. The electrode was notably reliable from the point of view of electrochemical performance and structural stability. Real sample analysis was also carried out by taking urine sample from adult male human.

Hydrogel/MOF Dual-Modified Photoelectrochemical Biosensor for Antibiofouling and Biocompatible Dopamine Detection.

For accurate in vivo detection, nonspecific adsorption of biomacromolecules such as proteins and cells is a severe issue. The adsorption leads to electrode passivation, significantly compromising both the sensitivity and precision of sensing. Meanwhile, common antibiofouling modifications, such as polymer coatings, still grapple with issues related to biocompatibility, electrode passivation, and miniaturization. Herein, we propose a composite antibiofouling coating strategy based on zwitterionic metal-organic frameworks (Z-MOFs) and a combination of acrylamide hydrogels. On a well-designed TiO2/Z-MOF/hydrogel photoelectrode, we achieve highly sensitive and selective detection of dopamine in complex biological environments. The hydrogel's three-dimensional porous structure combined with unique microporous architecture of Z-MOF ensures effective sieving of interfering macromolecules while preserving efficient small molecules and electron transport. This innovative approach paves the way for constructing miniature, in vivo antibiofouling sensors for molecule monitoring in living organisms with complicated chemical environments.

MnO2 nanosheets based catechol oxidase mimics for robust electrochemical sensor: Synthesis, mechanism and its application for ultrasensitive and selective detection of dopamine

Nanozymes have favorable activity and good stability, which are potential alternatives to natural enzymes and widely applied in biosensing. However, nanozymes based electrochemical sensors are fewer, because many nanozymes are not easy to form efficient electrocatalytic interface and experience interference from the possible oxidizable species. Herein, ultrathin MnO2 nanosheets (MnO2 NSs) were synthesized by reduction of KMnO4 in acidic environment by chemical precipitation method. The MnO2 NSs show excellent catechol oxidase mimicking activity. The steady-state kinetics of MnO2 NSs shows a higher Vmax of 3.441 µM s−1. Additionally, the catalytic mechanism is that in the presence of oxygen, catechol or its analogues are oxidized to quinone or quinoids, while oxygen is reduced to H2O. Afterwards, the possible mechanism of dopamine (DA) at MnO2 NSs-modified electrode is investigated. DA is first catalytically oxidized to dopamine quinone (DQ) by MnO2 NSs based catechol oxidase, which further undergoes irreversible electrochemical reduction to DA involving two protons and two electrons transfer during the process. On the basis of this, a selective and ultrasensitive amperometric detection of DA at 0.0 V (vs. SCE) was explored, which have two linear parts, 0.01–20 μM and 20–100 μM DA with the LOD of 4.1 nM (S/N = 3). Most importantly, the presence of oxidizable species including ascorbic acid, uric acid and cysteine may coexist with DA in biological systems do not exhibit any appreciable interference. The as-proposed method was applicable to detect DA in human serum samples with good satisfactory accuracy and recovery. This research casts prospect to apply nanozymes for electrochemical sensor with excellent analytical performance.

Tailored multi-layer graphene arrays for precision detection of neurotransmitter

The development of sensitive dopamine (DA) sensors has significantly contributed to our understanding of DA-related disorders and has enabled advancements in medical diagnostics and neuroscience research. Therefore, in the present work, a novel electrochemical sensing platform was developed using multi-layer graphene arrays (MGA) modified electrodes for the selective detection of DA. The preparation of high-quality MGA was achieved using the plasma-enhanced chemical vapor deposition (PCVD) method and was confirmed using various physiochemical techniques such as transmission electron microscopy and Raman spectroscopy. The modified electrode, made of MGA, was utilized for the electrochemical detection of DA using cyclic voltammetry and amperometry i-t methods. DA’s electrochemical oxidation response and sensitivity at the MGA electrode were ≈9 and 3 times higher than observed with unmodified and commercially available multi-layer graphene-modified electrodes. The MGA sensor exhibited excellent analytical parameters for DA detection, including a wide linear range of up to 172.1 μM and a low detection limit of 1.3 nM. The sensor also demonstrated remarkable sensitivity, storage stability, and selectivity for DA detection, making it highly suitable for accurately detecting DA in medical diagnostics and neuroscience research. Furthermore, the practical application of the MGA sensor for DA detection was demonstrated in various real samples.

Reliable ratiometric colorimetric monitoring of dopamine in practice based on the catalytic signal amplification of nano CeO2/CuO modified carboxylated chitosan

To reliably monitor dopamine (DA), a common neurotransmitter, a kind of nano CeO2/CuO modified carboxylated chitosan nanozyme (CeO2/CuO@CC) was constructed under microwave-assisted conditions. The proposed CeO2/CuO@CC exhibited superior synergistic- enhancement oxidase-like activity, with high specific surface area and superior stability. It could accelerate the oxidization of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) into blue oxTMB in the air. What’s more, the presence of trace DA could exclusively change the enzyme-like activity of CeO2/CuO@CC, accompanied with visual color changes from blue to colorless. Under the optimized conditions, there expressed double ratiometric linear relationships between lg(A652/A285)/lg(A370/A285) and cDA, with a large linear range between 6.0 × 10−9 and 1.0 × 10−5 M of DA. When applied for visual detection of DA in real samples, the detection limit was low to 2.0 × 10−9 M with RSD % less than 4.14 %. The mechanisms for enhanced oxidase-mimic activity of CeO2/CuO@CC and its selective detection of DA were proposed. This work will offer an insight to design efficient nanozyme for visual detection of bio-analytes in practice.

Graphene Nanocomposite Ink Coated Laser Transformed Flexible Electrodes for Selective Dopamine Detection and Immunosensing.

Novel and flexible disposable laser-induced graphene (LIG) sensors modified with graphene conductive inks have been developed for dopamine and interleukin-6 (IL-6) detection. The LIG sensors exhibit high reproducibility (relative standard deviation, RSD = 0.76%, N = 5) and stability (RSD = 4.39%, N = 15) after multiple bendings, making the sensors ideal for wearable and stretchable bioelectronics applications. We have developed electrode coatings based on graphene conductive inks, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (G-PEDOT:PSS) and polyaniline (G-PANI), for working electrode modification to improve the sensitivity and limit of detection (LOD). The selectivity of LIG sensors modified with the G-PANI ink is 41.47 times higher than that of the screen-printed electrode with the G-PANI ink modification. We have compared our fabricated bare laser-engraved Kapton sensor (LIG) with the LIG sensors modified with G-PEDOT (LIG/G-PEDOT) and G-PANI (LIG/G-PANI) conductive inks. We have further compared the performance of the fabricated electrodes with commercially available screen-printed electrodes (SPEs) and screen-printed electrodes modified with G-PEDOT:PSS (SPE/G-PEDOT:PSS) and G-PANI (SPE/G-PANI). SPE/G-PANI has a lower LOD of 0.632 μM compared to SPE/G-PEDOT:PSS (0.867 μM) and SPE/G-PANI (1.974 μM). The lowest LOD of the LIG/G-PANI sensor (0.4084 μM, S/N = 3) suggests that it can be a great alternative to measure dopamine levels in a physiological medium. Additionally, the LIG/G-PANI electrode has excellent LOD (2.6234 pg/mL) to detect IL-6. Also, the sensor is successfully able to detect ascorbic acid (AA), dopamine (DA), and uric acid (UA) in their ternary mixture. The differential pulse voltammetry (DPV) result shows peak potential separation of 229, 294, and 523 mV for AA-DA, DA-UA, and UA-AA, respectively.

ZnO-CeO2 Hollow Nanospheres for Selective Determination of Dopamine and Uric Acid.

ZnO-CeO2 hollow nanospheres have been successfully synthesized via the hard templating method, in which CeO2 is used as the support skeleton to avoid ZnO agglomeration. The synthesized ZnO-CeO2 hollow nanospheres possess a large electrochemically active area and high electron transfer owing to the high specific surface area and synergistic effect of ZnO and CeO2. Due to the above advantages, the resulting ZnO-CeO2 hollow spheres display high sensitivities of 1122.86 μA mM-1 cm-2 and 908.53 μA mM-1 cm-2 under a neutral environment for the selective detection of dopamine and uric acid. The constructed electrochemical sensor shows excellent selectivity, stability and recovery for the selective analysis of dopamine and uric acid in actual samples. This study provides a valuable strategy for the synthesis of ZnO-CeO2 hollow nanospheres via the hard templating method as electrocatalysts for the selective detection of dopamine and uric acid.

Electrochemically selective detection of dopamine over serotonin by CuO/Cu2O bulk heterostructure electrode

Electrochemically selective detection of dopamine over serotonin by CuO/Cu2O bulk heterostructure electrode

Nb4C3Tx MXene-AgNPs decorated laser-induced graphene for selective detection of dopamine

In this study, a selective electrochemical sensor based on Nb4C3Tx MXene-silver nanoparticles (Nb4C3Tx MXene-AgNPs) decorated laser-induced graphene (LIG) electrode synthesized from flexible pyralux film was employed to detect dopamine (DA). The characterization of the synthesized LIG, Nb4C3Tx MXene, and AgNPs was conducted using UV–visible spectroscopy, scanning electron microscopy, and Raman spectroscopy. The electrochemical performance of the fabricated LIG electrode was enhanced from a peak anodic current (Ipa) of 150 μA to 330.4 μA upon modification with Nb4C3Tx MXene-AgNPs nanocomposite. The LIG- Nb4C3Tx MXene-AgNPs electrode exhibited high electrocatalytic activity toward the oxidation of DA via cyclic voltammetry and chronoamperometry techniques. The current response increased linearly with DA concentration and exhibited a wide linear range from 100 nM to 10 µM with a detection limit of 1 nM. The sensor also exhibited an excellent sensitivity of 160.96 μA/nM cm−2. Furthermore, the fabricated LIG-Nb4C3Tx MXene-AgNPs electrode showed excellent selectivity toward DA detection in the presence of common interfering compounds such as glucose, ascorbic acid, and uric acid and had high reproducibility. The developed LIG-Nb4C3Tx MXene-AgNPs flexible electrode platform is suitable for accurately and reliably detecting DA in the presence of competing analytes.

Synthesis of graphene quantum dots inside a nanoreactor for fluorescence detection of dopamine

A label-free fluorescence sensor for selective detection of dopamine (DA) was developed by using graphene quantum dots (GQDs) as fluorescence probes. The GQDs were prepared via a top-down acid vapor oxidation strategy, in which a hollow carbon @ mesoporous silica nanosphere (h-C@mesoSiO2) serves as nanoreactor and only 1 mL of HNO3 was used as scissors for quickly cleaving the thin carbon layer in the nanospace of h-C@mesoSiO2. The method not only effectively avoids a tedious separation process but also endows GQDs with uniform size and good dispersion. And the as-prepared GQDs display good linear fluorescence response to DA in the range of 0.24–5.86 mM with a low detection limit of 12.7 nM. The proposed sensor shows high selectivity and satisfying recovery for DA detection in human urine. The good specificity toward DA may be due to a) the carboxyl groups on the surface of GQDs can interact with the amine functional groups in DA through electrostatic interactions and b) this specificity is further enhanced by the π–π interaction between GQDs and DA. Importantly, the work not only provides an avenue for the controllable synthesis of GQDs, but also expands the application of GQDs prepared by top-down method to DA sensor.

Fiber Optic SPR Sensor Modified With Copper Oxide Nanoparticles for Highly Sensitive and Selective Detection of Dopamine

Fiber Optic SPR Sensor Modified With Copper Oxide Nanoparticles for Highly Sensitive and Selective Detection of Dopamine

Porous gold-layered cubic and octahedral Cu-oxide nanocrystals: Dopamine sensing

Two morphologically different porous gold layered on Cu-oxide-based electrochemical sensors were developed for the selective detection of dopamine in the presence of uric acid, ascorbic acid or dextrose. The nanoparticles were prepared by layering Au onto either a cubic or octahedron-shaped Cu-oxide crystal via a galvanic reaction. These were characterized with scanning electron microscopy, energy dispersive X-ray and X-ray photoelectron spectroscopy. The porous structure of the gold over layer was clearly visible on the scanning electron microscopy image while the macro morphology was maintained. X-ray photoelectron spectroscopy confirmed the presence of metallic gold while both CuI (CuO) and CuII (Cu2O) were present in the samples. These two Au/Cu-oxide nanocomposites were used to modify glassy carbon electrodes and were tested for their dopamine sensing ability. Differential pulse voltammetry was used to investigate the selectivity towards dopamine in the presence of different interfering molecules uric acid, ascorbic acid and dextrose). From the differential pulse voltammetry, the lowest limit of detection was found to be 1.1 μM, with a sensitivity of 3.4 μA mM−1 mm−2 in the linear range of 10–250 μM for the porous gold layered covering the octahedron Cu-oxide-modified glassy carbon electrode.

3-aminophenylboronic acid modified carbon nitride quantum dots as fluorescent probe for selective detection of dopamine and cell imaging

Dopamine (DA) is the most abundant catecholamine neurotransmitter in the brain and plays an extremely essential role in the physiological activities of the living organism. There is a critical need for accurately and efficiently detecting DA levels in organisms in order to reflect physiological states. Carbon nitride quantum dots (C3N4) were, in recent years, used enormously as electrochemical and fluorescence probes for the detection of metal ions, biomarkers and other environmental or food impurities due to their unique advantageous optical and electronic properties. 3-Aminophenylboronic acid (3-APBA) can specifically combine with DA through an aggregation effect, providing an effective DA detection method. In this work, 3-APBA modified carbon nitride quantum dots (3-APBA-CNQDs) were synthesized from urea and sodium citrate. The structure, chemical composition and optical properties of 3-APBA-CNQDs were investigated by XRD, TEM, UV–visible, and FT-IR spectroscopy. The addition of DA could induce fluorescence quenching of 3-APBA-CNQDs possibly through the inner filter effect (IFE). 3-APBA-CNQDs shows better selectivity and sensitivity to DA than other interfering substances. By optimizing the experiment conditions, good linearity was obtained at 0.10–51 μM DA with a low detection limit of 22.08 nM. More importantly, 3-APBA-CNQDs have been successfully applied for the detection of DA in human urine and blood samples as well as for bioimaging of intracellular DA. This study provides a promising novel method for the rapid detection of DA in real biological samples.

Electroactive ferrites nanostructure driven electrochemical platform for selective detection of dopamine

This study proposes a new electrochemical platform based on electroactive vanadium ferrites (VFe2O4) for the highly selective detection of dopamine (DA). VFe2O4 were synthesized with the sol–gel auto-ignition method and characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), impedance analyzer, and cyclic voltammetry. The characterization study revealed that the VFe2O4 have a single-cubic structure with agglomerated structure. The VFe2O4 showed the multi-ions-based increment in the dielectric constant. The VFe2O4 sensor was fabricated by drop-casting method on a glassy carbon (VFe2O4-GCE) electrode with the addition of Nafion and applied for electrochemical detection of DA (a common neurotransmitter) in pharmaceutical preparations and biological samples. The results of electrochemical analysis of DA in the concentration range of 0.05 – 12.3 µM by using VFe2O4-GCE showed a linear response (co-efficient of determination R2 = 0.995) with the limit of detection and quantification (LOD/LOQ) as 0.0087 and 0.029 μM, respectively.

Self-assembly of simple Schiff base ligand into unique saddle-type [4x4] tetranuclear architecture and its application as selective voltammetric dopamine sensor in aqueous conditions

Dopamine, a crucial catecholamine neurotransmitter, plays essential roles in the operation of the central nervous system in humans. Disrupted dopamine release is associated with neurological disorders and depression, therefore monitoring of dopamine levels is imperative for preliminary disease detection. Development of sensitive and selective sensors for neurotransmitters that function under aqueous conditions is however still challenging, mostly due to the complexity of hybrid nanomaterials that are interacting with the electrode. Here we provide a coordination compound constructed from simple substrates, where subcomponent self-assembly leads to a unique, discrete [4 × 4] saddle-type complex [Cu4(L-H)4(BF4)2(MeOH)2](BF4)2, which was characterized by ESI-MS and FT-IR techniques, including single crystal X-ray diffraction. The Cu4L4 complex was subsequently used for modification of the bare Au electrode based on its accumulation on the electrode surface. The new voltammetric sensor (Au/complex) was applied for dopamine detection alone and in the presence of interfering ascorbic acid by using the Differential Pulse Voltammetry (DPV) techniques under aqueous conditions. In the linear dynamic range (LDR) range from 0.0001 mM to 0.75 mM the dependence of the peak current on dopamine concentration satisfied the following linear regression equation: ip [mA] = 17∙10−2cDA [mM] + 8∙10−2 (R2 = 0.998). Moreover, the excellent limit of dopamine detection (LOD) and the limit of its quantification (LOQ) were established at the level of 5.4 nM and 18.0 nM with accomplished high sensitivity 0.17 A M−1, repeatability as well as reproducibility. Clear separation of the voltammetric signal of dopamine from this one of ascorbic acid, even in the presence of a 100-fold excess of interfering ions found in water, consequently proves that the new prepared sensor can be used as an excellent analytical tool for selective detection of dopamine and ascorbic acid coexisting in the tested samples.

Eosin Y embedded Gd-MOF as a dual emission detection platform for dopamine

A 2D Gd-MOF {Gd-MOF = [Gd(L)(NO3) (DMF)2]n (H2L = 2,5-Bis(1,2,4-triazol-1-yl) terephthalic acid, DMF = N, N-dimethylformamide)} was synthesized based on solvothermal method. To achieve double emission peaks, Eosin Y embedded Gd-MOF (EY@Gd-MOF) was prepared through the synthetic encapsulating method. Due to the effective FRET between EY and Gd-MOF, EY@Gd-MOF shows double emission characteristic peaks. The ratio of emission peaks is used as the detection signal to replace the absolute fluorescence intensity of emission peak, and EY@Gd-MOF as a self-calibrated fluorescence sensor to detect dopamine, which realizes the selective detection of dopamine. Under optimal conditions of pH = 9, dopamine polymerizes to produce polydopamine, which attaches to the surface of EY@Gd-MOF and completely quenches the fluorescence of EY@Gd-MOF and the detection limit for dopamine is 0.124 μM. Because the excitation spectrum of Gd-MOF fully covers the ultraviolet absorption spectrum of polydopamine, energy competitive absorption is the major cause of fluorescence quenching. In addition, EY@Gd-MOF can be made into a test strip to detect dopamine, and also has the ability to detect in synthetic urine, providing a feasible scheme for the actual detection of dopamine.

Electrodeposited reduced graphene oxide-PEDOT:PSS/Nafion hybrid interface for the simultaneous determination of dopamine and serotonin

The electrochemically deposited reduced graphene oxide-PEDOT:PSS/Nafion (rGO-PP/NF) hybrid material has provided a favorable interface for the simultaneous detection of dopamine (DA) and serotonin (5-HT). The rGO-PP/NF onto the Au seed layer of the flexible substrate was simple, and it was followed by the sequential electrophoretic deposition of GO, reduction at the optimal pH buffer media, electropolymerization of EDOT:PSS, and Nafion coating. The strong electron-transport capacity between rGO-PEDOT:PSS and the negatively charged Nafion matrix might allow the highly sensitive, simultaneous, and selective detection of DA and 5-HT due to its high affinity for cations. In the results of the electrochemical response, well-separated oxidation peaks were observed in a mixture that contained various concentrations of DA and 5-HT. It showed the dynamic sensing of DA and 5-HT in the ranges of 0.5–75 μM and 0.05–50 μM, respectively, and the detection limits of 0.17 and 0.16 μM, respectively. In the mixture of DA and 5-HT, the sensor had a detection limit of 0.1 μM for 5-HT and DA, and its sensitivities of DA and 5-HT were 99.3 and 86 µA/µMcm2. Furthermore, it demonstrated high selectivity, reproducibility, stability, and a recovery property in the human serum spike test that was good enough for the practical use.

A disposable sensor based on one-pot synthesized tungsten oxide nanostructure-modified screen printed electrodes for selective detection of dopamine and uric acid.

Here, screen-printed carbon electrodes (SPCEs) were modified with ultrafine and mainly mono-disperse sea urchin-like tungsten oxide (SUWO3) nanostructures synthesized by a simple one-pot hydrothermal method for non-enzymatic detection of dopamine (DA) and uric acid (UA) in synthetic urine. Sea urchin-like nanostructures were clearly observed in scanning electron microscope images and WO3 composition was confirmed with XRD, Raman,FTIR and UV-Vis spectrophotometer. Modification of SPCEs with SUWO3 nanostructures via the drop-casting method clearly reduced the Rct value of the electrodes, lowered the ∆Ep and enhanced the DA oxidation current due to high electrocatalytic activity. As a result, SUWO3/SPCEs enabled highly sensitive non-enzymatic detection of DA (LOD: 51.4nM and sensitivity: 127µAmM-1cm-2) and UA (LOD: 253nM and sensitivity: 55.9µAmM-1cm-2) at low concentration. Lastly, SUWO3/SPCEs were tested with synthetic urine, in which acceptable recoveries for both molecules (94.02-105.8%) were obtained. Given the high selectivity, the sensor has the potential to be used for highly sensitive simultaneous detection of DA and UA in real biological samples.

3,5-Dihydroxybenzoic Acid-Based Selective Dopamine Detection via Subsititution-Enhanced Kinetics Differences.

The selective recognition of dopamine (DA) over other neurotransmitter analogues is difficult due to the similar molecular structure and chemical reactivity. In this study, substitution-regulated chemical reactivity of the sensing substrate is utilized to explore a novel DA detection probe with satisfying selectivity. As a case study, 3,5-dihydroxybenzoic acid (DHBA, carboxy-substituted resorcinol)-based probes have been explored for selective and ratiometric DA sensing. The carboxy substitution benefits the stabilization of the carbanion intermediate and the azamonardine product, which enhances the reaction kinetics and thermodynamics and subsequently facilitates selective DA recognition over other analogues and interferents. By exploring DHBA emission as the internal reference, ratiometric fluorescence variation is realized, which contributes to sensitive DA analysis. With the combination of logic gate and fluorometric analysis, DA detection in both low and high concentrations can be readily achieved. In addition, the DA analysis in biological samples and the enzymatic transformation of DA analogues in cerebrospinal fluid samples are achieved by the proposed DHBA probe.

Conductive PEDOT:PSS copolymer electrode coatings for selective detection of dopamine in ex vivo mouse brain slices

A novel voltammetric sensor was developed to selectively determine dopamine (DA) concentration in the presence of ascorbic acid (AA) and 3,4-dihydroxyphenylacetic acid (DOPAC). This sensor utilizes a modified pencil graphite electrode (PGE) coated with a newly synthesized poly (3,4-ethylene dioxythiophene) (PEDOT):poly (styrene sulfonate-co-2-(3-(6-Methyl-4-oxo-1,4-dihydropyrimidin-2-yl) ureido) ethyl methacrylate) (P(SS-co-UPyMA)) composite. The PEDOT:P(SS-co-UPyMA) (PPU) composite was characterized using nuclear magnetic resonance, X-ray photoelectron, and Raman spectroscopies. The PPU-coated PGE was characterized using electrochemical techniques, including cyclic and differential pulse voltammetry. Compared to uncoated, PPU-coated PGE demonstrated improved sensitivity and selectivity for DA. The sensor exhibited a dynamic linear range of 0.1–300 μM for DA, with a detection limit of 44.4 nM (S/N = 3). Additionally, the PPU-coated PGE showed high reproducibility and storage stability for four weeks. To demonstrate its practical applicability, the PPU-coated PGE sensor was used for ex vivo brain slice samples from control and Parkinson's disease model mice.