Dopamine Concentration Range Research Articles

Preparation of Au/α‐Fe2O3 Electrode for the Detection of Dopamine

AbstractIn this study, Au/α‐Fe2O3 sensing material was synthesized and used as the working electrode for dopamine sensing. The Au/α‐Fe2O3 composites were prepared with various loadings (0.5 %, 1 %, and 3 %) to enhance their sensing properties. All three composites were tested for dopamine sensing, with 1 % Au/α‐Fe2O3 showing the best response. The Au/α‐Fe2O3 composites were characterized using XRD, TEM, and SEM to confirm successful doping of Au on the iron oxide surface. The CV plot obtained by plotting Cyclic Voltammetry (CV) vs. dopamine (DA) was linear (R2=0.9872) for DA concentrations ranging from 6.25 μM–200 μM on 1 % Au/α‐Fe2O3. Similarly, the DPV plot between DPV vs. DA was linear (R2=0.9895) for the same DA concentration range on 1 % Au/α‐Fe2O3, with a detection limit of 0.19 μM. Interference and stability experiments were conducted with dopamine (DA), ascorbic acid (AA), and uric acid (UA). The results showed that DA sensing was not affected by the other two substances for up to 14 days. The signal results indicated that the current intensity remained at 90.75 % of the original, proving that this material has good stability.

Non-toxic flexible screen-printed MWCNT-based electrodes for non-invasive biomedical applications

Here, a non-toxic, flexible, low-cost, and disposable multiwalled carbon nanotube (MWCNT)-based screen-printed electrode (SPE) was developed for non-invasive health monitoring applications. A novel MWCNT-based conductive paste formulation was prepared and optimized for printing SPEs using a computer numerical control (CNC)-made stencil. The electrodes were electrochemically characterized and subjected to physical stress to investigate their mechanical durability in extreme situations such as heavy exercise. The reproducibility of the fabrication approach and the stability of the electrodes were also demonstrated. The electrochemical performance of the electrodes was tested with first dopamine (DA) and then glucose. The SPE displayed a linear response in the DA concentration range of 5–500 μM with a limit-of-detection (LOD) of 0.87 μM. Detection of glucose was carried out based on electrochemical-enzymatic redox cycling in artificial sweat; wherein the flexible SPE-based biosensor exhibited a linear response, particularly up to 1 mM with an LOD of 31.7 μM. It is likely that the high sensitivity was achieved due to the large surface-to-volume ratio of MWCNTs and micro/nanoporous network morphology of the electrode surface which was observed in scanning electron microscopy (SEM). Cytotoxicity tests confirmed that the flexible MWCNT-SPEs are non-toxic and therefore safe for non-invasive health monitoring. As a result, the electrodes displayed excellent electrochemical behavior and are expected to contribute to wearable sensor technology due to features such as high stability, sensitivity, flexibility, and non-toxicity.

Aluminum-Doped Zinc Oxide Enzymatic Dopamine Biosensor Integrated With Potentiometric Readout Circuit Board

In this study, the standard industrial flexible printed circuit board (FPCB) was employed to fabricate the potentiometric enzymatic dopamine (DA) biosensor. The aluminum-doped zinc oxide (AZO) was used to make the sensing films of the DA sensor. This sensing film was prepared by a radio frequency (RF) sputtering system. The thickness and surface morphology of the AZO films were observed by the field emission scanning electron microscope (FE-SEM), and the elemental composition and oxidation state of the films were analyzed through X-ray electron spectroscopy (XPS). Tyrosinase (Tyr) was used as the enzyme of the sensor, which was immobilized on AZO film with (3-Aminopropyl)triethoxysilane (APTES) and glutaraldehyde. After the sensor was prepared, we integrated the sensor and the readout circuit board through the FPCB connecter and then measured the sensing characteristics of the DA sensor in the DA concentration range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1~\mu \text{M}$ </tex-math></inline-formula> –10 mM. The sensing characteristics mostly include average sensitivity and linearity, limit of detection (LOD), interference effect, response time, reproducibility, flexibility, and lifetime. Based on the experimental results, the DA sensor in this study has good sensing characteristics. Through the enzyme, the sensor has good selectivity for DA in the presence of other relatively high concentrations interfered with biomolecules.

In situ green synthesis of the nanocomposites of MnO2/graphene as an oxidase mimic for sensitive colorimetric and electrochemical dual-mode biosensing.

Herein we report the colorimetry and an electrochemical for the determination of dopamine (DA) by using MnO2 nanoparticles and graphene nanosheets composite (MnO2@G) that display oxidase mimicking property. MnO2@G could directly oxidize colorless 3,3',5,5'-tetramethylbenzidine (TMB) into a blue product (oxTMB) without extra oxidants such as H2O2. Nevertheless, the presence of DA will inhibit the TMB oxidation due to the presence of the competitive reaction of MnO2@G and DA, giving a product color change from blue to colorless. A colorimetric assay for detect the concentration of DA was worked out according to this finding. Response is linear in the 0.1 to 15 μM DA concentration range, and the detection limit is 0.14 μM. Wider detection range is achieved in an electrochemical method which is due to the pronounced electrocatalytic activity of MnO2@G. The MnO2@G was modified on the surface of the glassy carbon electrode in order to fabricate one type electrochemical sensor. The sensor achieves a wide detection two linear ranges from 0.4 to 70 μM, with the detection limit of 1.16 μM. The detection of DA in real serum sample proved that the nanozyme based on MnO2@G could be developed into a colorimetry and electrochemical dual-readout sensing platform.

Femtomolar detection of dopamine using surface plasmon resonance sensor based on chitosan/graphene quantum dots thin film

Due to the crucial role of dopamine (DA) in health and peripheral nervous systems, it is particularly important to develop an efficient and accurate sensor to monitor and determine DA concentrations for diagnostic purposes and diseases prevention. Up to now, using surface plasmon resonance (SPR) sensors in DA determination is very limited and its application still at the primary stage. In this work, a simple and ultra-sensitive SPR sensor was constructed for DA detection by preparation of chitosan- graphene quantum dots (CS-GQDs) thin film as the sensing layer. Other SPR measurements were conducted using different sensing layers; GQDs, CS for comparison. The proposed thin films were prepared by spin coating technique. The developed CS-GQDs thin film-based SPR sensor was successfully tested in DA concentration range from 0 fM to 1 pM. The designed SPR sensor showed outstanding performance in detecting DA sensitively (S = 0.011°/fM, R2 = 0.8174) with low detection limit of 1.0 fM has been achieved for the first time. The increased angular shift of SPR dip, narrow full width half maximum of the SPR curves, excellent signal-to-noise ratio and figure of merit, and a binding affinity constant (KA) of 2.962 PM−1 demonstrated the potential of this sensor to detect DA with high accuracy. Overall, it was concluded that the proposed sensor would serve as a valuable tool in clinical diagnostic for the serious neurological disorders. This in turns has a significant socio-economic impact.

Construction of a Highly Selective and Sensitive Dopamine Enzyme‐free Biosensor Based on Carbon Nanomaterials

AbstractA selective and sensitive electrochemical enzyme‐free sensor for dopamine (DA) was prepared, containing carbon nanomaterials, gold nanoparticles (GNPs) and room‐temperature ionic liquid of 1‐butyl‐3‐methylimidazolium tetrafluor (BmimBF4). The peaks of DA, ascorbic acid (AA) and uric acid (UA) can be well separated by optimization of pH condition and carbon nanomaterials.Multi‐walled carbon nanotubes (MWCNTs), single‐walled carbon nanotubes (SWCNTs), single‐walled carbon nanohorns (SWCNHs), carboxylated graphene (C‐GR), were chosen to compare the affection to DA detection. The catalytic effect was SWCNTs&gt;MWCNTs&gt;C‐GR≈SWCNHs. It showed carbon nanotube materials with electron acceleration channels play the key role in catalytic performance. The pH condition also influenced detection, all the redox peak potentials of DA, UA, and AA had a negative shift as the pH changed from low to high, but the amplitude of the shift was different. At pH 1, the three anodic peaks are separated ca.0.24 V and 0.20 V. Under optimum conditions linear calibration graphs were obtained over the DA concentration range 0.2 to 20 μM.The modified electrode was applied for the assay of spiked DA in blood serum and human urine.This work studied the influence of carbon nanomaterials on DA detection and provided a simple approach to selectively detect dopamine in the presence of AA and UA.

NO2-functionalized metal–organic framework incorporating bimetallic alloy nanoparticles as a sensor for efficient electrochemical detection of dopamine

Abnormal levels of dopamine (DA), a critical neurotransmitter, can lead to various neurological disorders. A selective and sensitive method for detection of DA is therefore required for early diagnosis of such diseases. Herein, we report an approach to sensitive detection of DA using a metal–organic framework incorporating bimetallic alloy nanoparticles (AgPd@Zr-MOF). The as-synthesized MOF was characterized using different physicochemical techniques. The excellent DA sensing abilities of the fabricated material can be attributed to the high specific surface area and enormous number of electroactive sites. The electrochemical features and catalytic efficiency of a AgPd@Zr-MOF-modified glassy carbon electrode were investigated using electrochemical impedance spectroscopy, cyclic voltammetry, linear sweep voltammetry, and square wave voltammetry. The fabricated sensor exhibits a limit of detection of 0.1 μM, a linear DA concentration range of 2–42 μM, and a sensitivity of 10.26 μA μM−1 cm−2. The applicability of the fabricated sensor was tested in human urine and dopamine injection samples. The results of our study could lead to methods for the detection of other neurotransmitters in the near future.

Fiber-optic biosensor based on the laccase immobilization on silica-functionalized fluorescent carbon dots for the detection of dopamine and multi-color imaging applications in neuroblastoma cells

An efficient and cost-effective biosensor is of the great demand for the detection of the biologically significant neurotransmitter dopamine. In this context, enzymatic biosensors show excellent sensitivity and selectivity. In this study, we developed a laccase immobilized fiber-optic biosensor based on the fluorescence principle for the detection of dopamine. To design this biosensor, we used microwave irradiation to synthesize carbon dots (CDs) using curcumin and dimethylformamide, and the resulting CDs were called CDD-CDs. These were functionalized with a silicon precursor, 3-(aminopropyl)-triethoxysilane, and were referred to as APT-CDs. Furthermore, laccase was covalently immobilized to the APT-CDs to construct a novel bioprobe. The CDD-CDs, APT-CDs, and bioprobe showed orange (λem = 586 nm) green (λem = 533 nm), and blue-colored emissions (λem = 476 nm) at 430, 380, and 360 nm excitation wavelengths, respectively. The CDD-CDs and bioprobe showed quantum yields of 14.8% and 10.2%, respectively. The CDD-CDs displayed solvatochromism in various solvents. Bioprobe showed a significant fluorescence quenching for dopamine in the linear range of 0–30 μM with a detection limit of 41.2 nM. Bioprobe was immobilized on the tapered optical fiber using ethyl cellulose by a simple dip-coating method and investigated for multi-color imaging applications. The resulting tapered optical fiber achieved a satisfactory detection limit of 46.4 nM in the dopamine concentration range of 0–10 μM. The bioprobe demonstrated high biocompatibility, long-lasting photostability, and thermal stability, and had sufficient cytotoxicity in human neuroblastoma cells (SH-SY5Y) with excellent multi-color imaging potential. The practicality of the bioprobe was investigated in human serum and cerebrospinal fluid.

Self-rolled TiO2 microscroll/graphene composite for electrochemical dopamine sensing

Dopamine is an important neurotransmitter, and nonenzyme electrochemical sensor of dopamine detection based on highly active material is urgently demanded. In this work, an electrochemical sensor with high sensitivity and selectivity based on self-rolled TiO2 microscroll/graphene composite was developed and validated for dopamine sensing. The device exhibited a superior performance for dopamine detection with a detection limit of 4.25 × 10-9 mol L-1, and in the dopamine concentration range of 0.06–90 μmol L-1, the oxidation currents increased linearly with the concentration. The remarkable performance enhancement was mainly ascribed to the increased surface area due to the porous surface of the TiO2 nanomembrane and highly conductive graphene therein. In addition, we have demonstrated that the sensor could be effectively used on detecting dopamine concentrations in urine samples. Our work demonstrates that the current microscroll-based device is promising in the field of real-time health monitoring for future human community.

Ultrasensitive dopamine detection of indium-zinc oxide on PET flexible based extended-gate field-effect transistor

With the aim of a simple, label-free, and highly specific dopamine detection, we proposed an indium-zinc oxide (InZnxOy) sensing film on flexible PET using a simple sol-gel method for an extended gate field-effect transistor (EGFET) sensor. In this study, X-ray diffraction, atomic force spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the structural, morphological, and chemical features, respectively. The InZnxOy based EGFET sensor showed a super Nernstian pH response of 61.53 mV/pH with an excellent linearity of 0.995 (in the range of pH 2–12), a low hysteresis voltage of ∼ 3 mV (in the pH loop of 7→4→7→10→7) and a small drift rate of 3.52 mV/h (in the pH 7). Correspondingly, to investigate the impact of mechanical bending on the pH performances of InZnxOy based flexible EGFET sensor, a couple of bending tests, which include different bending radius and bending cycles, were performed. The device showed better mechanical durability up to 1500 bending cycles for pH sensitivity. In order to achieve the label-free detection of dopamine, the InZnxOy on PET-based EGFET was functionalized using a synthetic receptor named 4-carboxylphenylboronic acid, for the covalent binding of dopamine on the sensing surface. The sensitivity of dopamine is 10.69 mV/log(dopamine) with linearity 0.998 within the dopamine concentration range of 1 fM–1 nM and the limit of detection value is 0.523 fM. In addition, this InZnxOy based EGFET biosensor showed excellent selectivity to dopamine over other interfering chemicals. Our proposed InZnxOy EGFET biosensor was successfully applied to detect dopamine level in the real samples like rat blood serum and rat brain.

Nitrogen-doped carbon frameworks decorated with palladium nanoparticles for simultaneous electrochemical voltammetric determination of uric acid and dopamine in the presence of ascorbic acid.

A glassy carbon electrode (GCE) was modified with nitrogen-enriched carbon frameworks decorated with palladium nanoparticles (Pd@NCF/GCEs). The modified GCE is shown to be a viable tool for determination of uric acid (UA) and dopamine (DA) in the presence of ascorbic acid (AA). The Pd@NCF was fabricated though one-step pyrolysis and characterized by X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy and nitrogen-adsorption/desorption analysis. The Pd@NCF/GCE was characterized by differential pulse voltammetry (DPV). Both UA and DA have pronounced oxidation peaks (at 360mV for UA and 180mV for DA, all vs. Ag/AgCl) in the presence of AA. Response is linear in the 0.5-100μM UA concentration range and in the 0.5-230μM DA concentration range. The detection limits are 76 and 107nM, respectively (at S/N = 3). This electrode is stable, reproducible and highly selective. It was used for UA and DA determination in spiked serum samples. Graphical abstractSchematic representation of nitrogen-enriched carbon frameworks decorated with palladium nanoparticles co-modified glassy carbon electrode for simultaneous determination of dopamine and uric acid in the presence of ascorbic acid.

Graphite paste electrodes modified with a sulfo-functionalized metal-organic framework (type MIL-101) for voltammetric sensing of dopamine.

The metal-organic frameworks MIL-101 and sulfo-MIL-101 were used to modify graphite paste electrodes (GPEs) to obtain sensors for determination of dopamine (DA). Taking advantage of the catalytic activity of metal-organic frameworks (MOFs) and of the electrical conductivity of graphite, the modified GPEs show enhanced voltammetric responses, and the GPE modified with the sulfo-MOF displays superior sensitivity when operated at a working potential of -0.4 to 0.8V (vs. Ag/AgCl). The sensor works in the 0.07 to100 μM DA concentration range and has a 43nM detection limit. It is concluded that the sulfo group provides open sites for efficient electrostatic and hydrogen bonding interactions, which facilitates electron transfer. Graphical abstractSchematic representation of the structure of the sulfo-functionalized MOF (sulfo-MIL-101) and the different voltammetric signals of dopamine at the graphite paste electrodes (GPEs) modified with sulfo-MIL-101 and the parent MOF (MIL-101).

In-situ graft-crosslinked gold nanoparticles with high-density surface defects and coated with a polytaurine membrane for the voltammetric determination of dopamine

Well-dispersed and graft-crosslinked gold nanoparticles (AuNPs) were synthesized by the reduction of tetrachloroaurate with hydrazine at room temperature. The AuNPs possess a high density of surface defects which is due to grafting of n-octanoic acid to polyvinylpyrrolidone. The physical and chemical properties of the resulting AuNPs were characterized by UV-vis, XRD, TEM/HRTEM, SAED, and XPS, respectively. The modified AuNPs were placed on a glassy carbon electrode (GCE) in an electropolymerized taurine layer to obtain a sensitive, selective, stable and rapid electrochemical dopamine sensor. The peak current, typically measured at 0.17V (vs. SCE), increases linearly in the 1.0 to 120μM dopamine concentration range, and the limit of detection (at S/N= 3) is 0.16μM with a sensitivity of 2.94μA·μM-1·cm-2. The sensor was successfully applied to the determination of dopamine in injections and spiked serum samples. The recoveries from spiked serum samples range from 97.5 to 102.4%, with RSDs ranging between 2.8 and 3.4%. Graphical abstract Schematic representation of a glassy carbon electrode modified with in-situ graft-crosslinkedgold nanoparticles combined with an electropolymerized polytaurine membrane. The sensor exhibits excellent features towards dopamine determination.

Photoelectrochemical sensing of dopamine using gold-TiO2 nanocomposites and visible-light illumination.

A photoelectrochemical (PEC) method was developed for the determination of dopamine. It is making use of a composite prepared from gold nanoparticles and TiO2 (type P25) and placed on a fluorine-doped tin oxide (FTO) electrode. The composites are used for photoelectrical detection with improved electron transfer efficiency for photoproduction and with improved photoelectrical conversion efficiency. This is due to the excellent electrical conductivity and surface plasmon resonance absorption by gold nanoparticles, and also by the photocatalytic effect of TiO2. Dopamine binds easily to the surface of the composites and acts as an electron donor. This electrode gives a strongly enhanced photocurrent which increases linearly in the 0.1 to 100μM dopamine concentration range and has a 23nM detection limit (at S/N = 3). The electrode was operated over 15cycles of light-on and light-off states every 20s under visible-light illumination, and the sensor indicates good stability. In addition, it is selective over several possible interferents including uric acid, L-cysteine, glutathione, ascorbic acid and glucose. Graphical abstract A new gold/P25 composite-based photoelectrochemical sensing scheme for dopamine is described. Under visible light irradiation, the photocurrent response is increased with the increasing concentration of dopamine (DA).

Electrochemically reduced graphene oxide and gold nanoparticles onan indium tin oxide electrode for voltammetric sensing of dopamine.

The authors describe an electrochemical dopamine sensor that is based on the use of electrochemically co-reduced graphene oxide (Er-GO) and gold nanoparticles (AuNPs) on an indium-tin oxide (ITO) electrode. The synergistic effects of Er-GO and Er-AuNPs promote electron transport in the modified ITO. This results in an excellent performance for voltammetric sensing of dopamine (DA). Under the optimum conditions and a typical working potential of -0.05V (vs. Ag/AgCl), the ITO electrode has a linear response in the 0.02-200μM DA concentration range and a low detection limit of 15nM. The sensor also showed a good selectivity over ascorbic acid and uric acid. The feasibility of the method was studied by analyzing DA in cerebrospinal fluid of rats. Graphical abstract Schematic presentation of one-step electrochemical co-reduction of graphene oxide (GO) and gold nanoparticles (AuNPs) on anITO electrode for voltammetric sensing of dopamine.

Polydopamine-coated carbon nanodots are a highly selective turn-on fluorescent probe for dopamine

Carbon nanodots (CDs) were prepared by the pyrolysis of lactose in hot alkali solution for 5 min. The resulting CDs possess spherical and monodisperse shape with an average diameter of ∼3 nm. The blue fluorescence of the CDs, with excitation/emission peaks at 414/470 nm, can be turned-on in the presence of very low concentrations of dopamine (DA) due to the formation of a poly-DA shell on the CDs. Fluorescence is only enhanced by DA, while other chemically related compounds do not interfere. Fluorescence increases linearly in the 1.0–10.0 μM DA concentration range, with a 0.22 μM lower detection limit. The nanoprobe was applied to the determination of DA in injections and in spiked urine samples, and the results compared well with those obtained by HPLC. The nanoprobe has a fast response, is inexpensive and highly selective.

Surface Plasmon Resonance Based Highly Selective Fiber Optic Dopamine Sensor Fabricated Using Molecular Imprinted GNP/SnO2 Nanocomposite

Fabrication and characterization of a highly selective fiber optic surface plasmon resonance-based dopamine sensor using molecular imprinted graphene nanoaplatelets/tin oxide (SnO2) nanocomposite have been reported. The synthesis of sensing layer has been carried out using a series of optimizations and morphological studies. The effectiveness of the sensing layer over other possible probe designs has been proved by performing control experiments for a dopamine concentration range covering the suggested level of dopamine for human being. The limit of detection (LOD) of the sensor evaluated is 0.031 μM, which is lower than the LOD values of various dopamine sensors fabricated using different methods. The specificity of the sensor for dopamine has been confirmed by performing experiments using various interferands while the stability and reusability of the sensor probe have been checked by performing experiments repeatedly for a long period of time. Apart from high sensitivity, low LOD, and fast response, the sensor can be used for remote sensing and online monitoring of dopamine.

Colorimetric determination of dopamine by exploiting the enhanced oxidase mimicking activity of hierarchical NiCo2S4-rGO composites.

A composite consisting of NiCo2S4 and reduced graphene oxide (rGO) was prepared via a hydrothermal process. Compared to individual NiCo2S4 nanomaterials or reduced graphene oxide, the composite exhibits enhanced oxidase-like activity. It is found that dopamine (DA) inhibits the ability of NiCo2S4-rGO to oxidize the substrate 3,3',5',5'-tetramethylbenzidine (TMB) to form blue colored ox-TMB. Based on these findings, a colorimetric method for determination of DA was workedout. The absorption, best measured at 652nm, increases linearly in the 0.5-100μM DA concentration range, and the limit of detection is 0.42μM. This method was successfully applied to the detection of DA in spiked human serum samples. Graphical abstract A hierarchical NiCo2S4-rGO composite was prepared through two-step hydrothermal process. It exhibits enhanced oxidase-like activity which, however, is inhibited by dopamine (DA).Hence, less blue colored ox-TMB is formed by oxidation of3,3',5,5'-tetramethylbenzidinein the presence of dopamine.

A glassy carbon electrode modified with a composite consisting of gold nanoparticle, reduced graphene oxide and poly(L-arginine) for simultaneous voltammetric determination of dopamine, serotonin and L-tryptophan.

A glassy carbon electrode (GCE) was modified with poly(L-arginine) (P-Arg), reduced graphene oxide (rGO) and gold nanoparticle (AuNP) to obtain an electrode for simultaneous determination of dopamine (DA), serotonin (5-HT) and L-tryptophan (L-Trp) in the presence of ascorbic acid (AA). The modified GCE was prepared via subsequent 'layer-by-layer' deposition using an electrochemical technique. The surface morphology of the modified electrode was studied by scanning electron microscopy, and electrochemical characterizations were carried out via cyclic voltammetry and electrochemical impedance spectroscopy. The modified electrode showed excellent electrocatalytic activity toward DA, 5-HT and L-Trp at pH7.0. Figures of merit for the differential pulse voltammetric reponse are as follows: (a) Response to DA is linear in two intervals, viz. 1.0-50nM and 1.0-50μM DA concentration range, the typical working voltage is 202mV (vs. Ag/AgCl), and the detection limit is 1nM (at an S/N ratio of 3). For 5-HT, the respective data are 10 to 500nM and 1.0 to 10μM, 381mV, and 30nM. For L-Trp, the respective data are 10-70nM and 10-100μM, 719mV, and 0.1μM. The modified GCE is fairly selective. It was successfully applied to the simultaneous determination of DA, 5-HT, and L-Trp in spiked urine samples, and high recovery rates were found. Graphical abstract Schematic presentation of the voltammetric sensor based on a glassy carbon electrode modified with poly(L-arginine), reduced graphene oxide (rGO) and gold nanoparticle (GCE/P-Arg/ErGO/AuNP) for simultaneous determination of dopamine (DA), serotonin (5-HT) and L-tryptophan (L-Trp).

Electrochemical dopamine sensor using a nanoporous gold microelectrode: a proof-of-concept study for the detection of dopamine release by scanning electrochemical microscopy.

Nanoporous gold (NPG) structures were prepared on the surface of a gold microelectrode (Au-μE) by an anodization-reduction method. Cyclic voltammetry and field emission scanning electron microscopy were used to study the electrochemical properties and the morphology of the nanostructured film. Voltammetry showed an improved sensitivity for dopamine (DA) oxidation at this microelectrode when compared to a bare gold microelectrode, with a peak near 0.2 V (vs. Ag/AgCl) at ascan rate of 0.1Vs-1. This is due to the increased surface area and roughness. Square wave voltammetry shows a response that is linear in the 0.1-10μmolL-1 DA concentration range, with a 30 nmol L-1 detection limit and a sensitivity of 1.18mA (μmolL-1)-1cm-2. The sensor is not interfered by ascorbic acid. The reproducibility, repeatability, long-term stability and real sample analysis (spiked urine) were assessed, and acceptable performance was achieved. The "proof-of-concept" detection of dopamine release was demonstrated by using scanning electrochemical microscopy (SECM) with the aim of future applications for single cell analysis. Graphical abstract A reproducible electrochemical approach was proposed to fabricate an NPG-microelectrode for DA detection, with enhanced sensitivity and selectivity. Besides, a proof-of-concept detection of DA release was also demonstrated by using SECM.