Graphene Gold Nanoparticles Research Articles

Amperometric lactate nanobiosensor based on reduced graphene oxide, carbon nanotube and gold nanoparticle nanocomposite.

A sensitive amperometric method is reported for the determination of lactate. A platinum electrode was modified with a composite prepared from reduced graphene oxide (rGO), carbon nanotubes (CNTs) and gold nanoparticles. The composite was synthesized by the in-situ reduction of gold(III) ions on the GO-CNT hybrid. Triple composite components showed synergistic effects on the enzyme loading, electrocatalytic activity and electron transfer between receptor and electrode surface. The amperometric lactate sensor was obtained by immobilization of lactate oxidase (LOx) on the modified electrode. LOx catalyzes the conversion of lactate into pyruvate and hydrogen peroxide. The generated hydrogen peroxide is simultaneously involved in the oxidation reaction, which is associated with the electron production. These electrons act as amperometric signal generators. At the low potential of 0.2V, the nanobiosensor shows a relatively wide linear analytical range (i.e., 0.05-100mM of lactate) with high electrochemical sensitivity (35.3μA mM-1 cm-2) and limit of detection of 2.3μM. The sensor is stable, repeatable and reproducible. It is a highly sensitive tool for the detection of lactate in biological samples under both normoxic and hypoxic conditions. Graphical abstract Schematic representation of an electrochemical biosensor for sensitive detection of lactate in biological and food samples based on reduced graphene oxide-carbon nanotube-gold nanocomposite, as a surface modifier, and lactate oxidase, as a bioreceptor.

A new electrochemical sensing platform for quantitative determination of diclofenac based on gold nanoparticles decorated multiwalled carbon nanotubes/graphene oxide nanocomposite film

ABSTRACT This paper describes a simple method for determination of diclofenac using a gold electrode modified with functionalised multiwalled carbon nanotubes (f-MWCNTs)/graphene oxide (GO) nanocomposite film and gold nanoparticles (AuNPs). Electrochemical deposition method was employed for immobilisation of AuNPs at the surface of f-MWCNTs-GO nanocomposite film. The microscopic structure and morphology of the prepared films at the surface of the electrode were characterised by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and electrochemical impedance spectroscopy (EIS). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to study the electrochemical behaviour of diclofenac molecules. The effect of several parameters such as pH, electrodeposition time and the amount of nanocomposite controlling the performance of the sensor was examined and they were optimised. The proposed sensor showed an excellent catalytic activity towards the oxidation of diclofenac molecules. The oxidation peak current of diclofenac was linear in the concentration ranges of 0.4–80 µM and 100–1000 µM with a detection limit of 0.09 μM. The modified electrode was used for the quantitative determination of diclofenac in water, tablet and human urine samples where it gave recoveries ranging between 98.8% and 105%

Construction of ZIF-8/AuNPs/PVP–rGO/GCE Electrochemical Sensor and Its Sensitive Determination of Salbutamol

An excellent electrochemical sensor based on glassy carbon electrode (GCE) modified in order with polyvinyl pyrrolidone-dispersed reduced graphene oxide (PVP–rGO), gold nanoparticles (AuNPs) and metal-organic framework material of ZIF-8 was fabricated for the highly sensitive determination of salbutamol (SAL). The modified materials and electrodes were characterized and investigated by X-ray diffraction (XRD), fourier transform infrared (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), electron dispersive X-ray (EDX), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The results indicated that ZIF-8/AuNPs/PVP–rGO/GCE exhibited a superior performance with a high sensitivity and selectivity as well as a satisfied stability and reproducibility for the determination of SAL because the self-assembled sensor was possessed of a large number of pores to promote the adsorption of SAL on its surface and offered the electron transfer environment to speed the electrochemical redox reaction of SAL remarkably. The SAL determination limit was as low as 1.00 × 10–12 mol/L under the optimum conditions with a linear range from 1.00 × 10–12 to 5.00 × 10–9 mol/L and a correlation coefficient (R) of 0.9985. Based on SAL electrochemical redox process of one-proton and one-electron involved, the possible redox mechanism of SAL on ZIF‑8/AuNPs/PVP–rGO/GCE was proposed. Furthermore, the electrochemical sensor was used for the detection of SAL in real pork samples and a well-pleasing result was achieved.

A nanocomposite prepared from reduced graphene oxide, gold nanoparticles and poly(2-amino-5-mercapto-1,3,4-thiadiazole) for use in an electrochemical sensor for doxorubicin.

A nanocomposite was prepared with reduced graphene oxide, gold nanoparticles and an electropolymerized film made from 2-amino-5-mercapto-1,3,4-thiadiazole. An electrochemical sensor for doxorubicin (DOX) was constructed by modifying a glassy carbon electrode (GCE) with the nanocomposite. The modified GCE was studied by electrochemical techniques which showed it to enable highly sensitive sensing of DOX. Response (typically measured at a typical working potential of -0.56V vs. Ag/AgCl) is linear in the 30 pM to 30nM and 30nM to 30μM DOX concentration ranges, with a limit of detection (LOD) of 9 pM (at an S/N ratio of 3). The method was applied to the determination of DOX in serum and gave recoveries that ranged between 92 and 108%. Graphical abstract A combination of materials consistingof reduced graphene oxide (rGO), gold nanoparticles (AuNPs) and an electropolymerized film of 2-amino-5-mercapto-1,3,4-thiadiazole (poly-AMT, PAMT) is described. The nanocomposite was placed on a glassy carbon elkectrode (GCE) in order to fabricate an electrochemical sensor for doxorubicin (DOX).

A highly sensitive competitive immunosensor based on branched polyethyleneimine functionalized reduced graphene oxide and gold nanoparticles modified electrode for detection of melamine

Branched polyethyleneimine functionalized reduced graphene oxide (BPEIGn) was prepared by a one-step reaction, catalyzed by NaOH, using branched polyethyleneimine (BPEI) and graphene oxide (GO) without reductant hydrazine hydrate or sodium borohydride. The branched polyethylenimine acted as both a grafting agent and a reducing agent of GO. An competitive electrochemical immunosensor based on the Au/sodium mercaptopropanesulfonate/BPEIGn/gold nanoparticles/melamine (Au/MPS/BPEIGn/AuNPs/Mel) modified electrode was constructed for the determination of melamine. The double amplification of BPEIGn and AuNPs increased the sensitivity of the sensor. The melamine was detected by differential pulse voltammetry (DPV) in buffer solution (pH 7.4) containing K3(Fe(CN)6]/K4[Fe(CN)6]. Under optimized conditions, the proposed melamine immunosensor showed a linear relationship in the concentration range of 1 × 10−6 to 1 μM, with a detection limit of 2.66 × 10−7 μM.

Ultrasensitive Paper-based ELISA by Introducing Atom Transfer Radical Polymer-modified Graphene Oxide Sheets and Gold Nanoparticles

In recent years, enzyme-linked immunosorbent assay (ELISA) plate fabricated on paper (P-ELISA) has been well developed. However, low sensitivity is its main disadvantage and has limited its use. In this study, a modified strategy was developed by introducing atom transfer radical polymer (ATRP)-modified graphene oxide (GO) sheets and gold nanoparticles (GNs). The results suggest the ATRP/GO/GNs-modified P-ELISA (AGGP-ELISA) achieves 1024 fold amplification and is suitable for rapid identification and qualitative detection, especially in small laboratories, or developing countries.

Electrochemical Aflatoxin B1 immunosensor based on the use of graphene quantum dots and gold nanoparticles

Electrochemical immunosensor for aflatoxin B1 (AFB1) is described that uses a composite prepared from graphene quantum dots (GQDs) and gold nanoparticles (Au NPs). The GQD-AuNP conjugate was obtained by using 2-aminothiophenol (ATP) as a linker where the carboxy groups of GQD bind to the amino groups of crosslinker via conjugation of thiol binding to the AuNP. To evaluate the conjugation of the GQD-AuNP composite, Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM) was applied. The composite was placed on an indium tin oxide (ITO) electrode and then modified with an antibody against AFB1. By using hexacyanoferrate as the electrochemical probe, the sensor works in the 0.1 to 3.0ngmL-1 AFB1 concentration range, is highly specific, has good reproducibility and acceptable stability. The biosensor was applied to the analysis of (spiked) maize samples. Conceivably, the method can be utilized to sense other mycotoxins by using their respective antibodies. Graphical abstract Schematic presentation of electrochemical immunosensor for Aflatoxin B1 (AFB1) detection developed by antibodies of AFB1 (anti-AFB1) immobilization on graphene quantum dots (GQDs)-gold nanoparticles (AuNPs) composite deposited by electrophoretic deposition technique on an Indium tin oxide (ITO) surface.

Electrochemical sandwich aptasensor for the carcinoembryonic antigen using graphene quantum dots, gold nanoparticles and nitrogen doped graphene modified electrode and exploiting the peroxidase-mimicking activity of a G-quadruplex DNAzyme.

A sandwich-type electrochemical aptasensor has been constructed and applied for sensitive and selective detection of the carcinoembryonic antigen (CEA). The surface of a glassy carbon electrode (GCE) was first modified with nitrogen-doped graphene and then gold nanoparticles and graphene quantum dots electrodeposited on it to obtain an architecture of type GQD/AuNP/NG/GCE. In the next step, the CEA-binding aptamer was immobilized on the modified GCE. Hemin intercalates in the amino-modified hemin aptamer to form a hemin-G-quadruplex (hemin-G4) DNAzyme. The amino modified CEA aptamer II is connected to hemin-G4 by glutaraldehyde (GA) as a linker to produce CEAaptamerII/GA/hemin-G4 (=ApII/GA/DNAzyme). Through a sandwich mode, the ApII/GA/DNAzyme bioconjugates are captured on the modified GCE. Subsequently, the hemin-G4 acts as peroxidase-mimicking DNAzyme and rapidly catalyzes the electroreduction of hydrogen peroxide. The quantitative determination of CEA was achieved by differential pulse voltammetry, best at a working potential of around -0.27V vs. Ag/AgCl. Under optimized conditions, the assay has a linear response in the 10.0fgmL-1 to 200.0ngmL-1 CEA concentration range and a lower detection limit of 3.2fgmL-1. Graphical abstract Schematic presentation of a sandwich-type electrochemical aptasensor based on nitrogen doped graphene (NG), gold nanoparticles (AuNPs) and graphene quantum dots (GQDs) modified glassy carbon electrode, and thehemin-G4 DNAzyme for femtomolar detection of thecarcinoembryonic antigen.

Composite Electrode Material Based on Electrochemically Reduced Graphene Oxide and Gold Nanoparticles for Electrocatalytic Detection of Ascorbic Acid

A nanostructured composite matrix containing gold nanoparticles (AuNPs), graphene oxide (GO), and Nafion was immobilized on the surface of a glassy carbon electrode (GCE) by drop casting. The GO was electrochemically reduced (erGO), in order to obtain a modified interface (GCE/AuNPs-erGO-Nafion) able to detect l-ascorbic acid (AA) at lower oxidation potentials with increased sensitivity. The obtained modified electrode was investigated by cyclic voltammetry, electrochemical impedance spectroscopy (EIS), and amperometry. The corroborated results showed that erGO and AuNPs at the interface act as a unique material having both high surface area (due to erGO) and high conductivity (due to AuNPs), being an effective electron transfer promoter in the electro-oxidation process of AA, lowering the oxidation potential of AA by ca. 0.400 V vs. Ag/AgCl,KClsat. The analytical parameters for AA detection at the modified GCE/AuNPs-erGO-Nafion electrode were determined by amperometry with a sensitivity of 39.07 ± 1.36 μA/mM and a detection limit of 2.76 μM AA (signal/noise ratio of 3). The GCE/AuNPs-erGO-Nafion-modified electrode is simple to prepare, reliable, and with high sensitivity and was applied successfully in the routine analysis of AA in pharmaceutical products.

Gold nanoparticles decorated rGO-ZnCo2O4 nanocomposite: A promising positive electrode for high performance hybrid supercapacitors

Herein, we have engineered gold nanoparticles decorated reduced graphene oxide-ZnCo2O4 hybrid material by a hydrothermal process. With exercising benefit of a synergistic influence of reduced graphene oxide and gold nanoparticles, the nanohybrid ensures that internal microstructure is altered from ZnCo2O4 microflower to Au@rGO-ZnCo2O4 cauliflower. The prepared Au@rGO-ZnCo2O4 cauliflower electrode shows a high specific capacity of 288.5 mAh g−1 at 2 mV s−1 scan rate. The more detailed electrochemical interpretation is carried out to understand the charge storage abilities of the electrodes occurred from the capacitive- and diffusion-controlled kinetics processes. These excellent electrochemical performances can be assigned to the incorporation of gold nanoparticles and reduced graphene oxide nanosheets that alleviate electrons exchange and transmit through electrochemical active sites, which create an electronic and structural heterogeneity of the electro-active material. Further, Au@rGO-ZnCo2O4//AC hybrid solid-state supercapacitor cell is designed with polymeric gel electrolyte that delivered a good power density of 2121 W kg−1 at an energy density of 31 Wh kg−1 with excellent capacitance retention over 5000 cycles highlights convenience of the utility of mixing high capacity with high electronic transport. The experimental results reveal that the noble metal nanoparticles incorporated hybrid nanostructures are promising electrode materials for energy storage applications.

A disposable electrochemical sensor based on electrospinning of molecularly imprinted nanohybrid films for highly sensitive determination of the organotin acaricide cyhexatin.

Nanofibrous polyporous membranes imprinted with cyhexatin (CYT) were formed via the ordered distribution of the imprints in electrospun nanofibers. The MIPs have a high mass transfer rate and enhanced adsorption capacity. In addition, a printed carbon electrode with enhanced sensitivity was developed via electrochemical fabrication of reduced graphene oxide (rGO) and gold nanoparticles (AuNPs). The molecularly imprinted sensor exhibits excellent selectivity and sensitivity for CYT. The structure and morphology of the nanohybrid films were characterized by using scanning electron microscopy, atomic force microscopy and chronoamperometry. The sensing performances were evaluated by cyclic voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy by using hexacyanoferrate(IV) as an electrochemical probe. The electrode, best operated at a working potential of around 0.16V (vs. Ag/AgCl), has a linear response in the1-800ngmL-1 CYT concentration range and a detection limit of 0.17ngmL-1 (at S/N = 3). The sensor demonstrated satisfactory recoveries when applied to the determination of CYT in spiked pear samples. Graphical abstract Schematic presentation of the electrochemical sensor for detection of CYT.

A Highly Sensitive Determination for the Melamine in Milk on MIL-101/AuNPs/CTS-PVP-rGO/GCE Electrochemical Sensor

A highly sensitive melamine electrochemical sensor was successfully constructed by self-assembling based on the composite of chitosan with polyvinyl pyrrolidone-dispersed reduced graphene oxide (CTS-PVP-rGO), gold nanoparticles (AuNPs) and metal-organic framework MIL-101. The characterizations of modified materials and electrodes were investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), electron dispersive X-ray (EDX) spectroscopy, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). The results indicated that the sensor of MIL-101/AuNPs/CTS-PVP-rGO/GCE exhibited a high sensitivity and selectivity as well as a good stability and reproducibility for the determination of melamine since CTS-PVP-rGO or AuNPs could enhance the conductivity of the sensor greatly and MIL-101 could promote the adsorption of melamine on the surface of the modified electrode remarkably. At pH 7.0, the scan rate of 100 mV/s and the frequency of 50 Hz, the determination limit of melamine was as low as 5.00 × 10–11 mol/L with the linear range from 5.00 × 10–11 to 1.00 × 10–8 mol/L and the correlation coefficient (R) of 0.996. Based on the electrochemical behavior of melamine on MIL-101/AuNPs/CTS-PVP-rGO/GCE, the possible redox procedure of melamine was put forward. Furthermore, the sensor of MIL-101/AuNPs/CTS-PVP-rGO/GCE was applied to the determination of melamine in milk products and a satisfying result was obtained.

Sensitive detection of dopamine using a platinum microelectrode modified by reduced graphene oxide and gold nanoparticles

Platinum wire microelectrodes generally exhibited properties of low sensitivity but are easily contaminated where it comes to dopamine detection. In this paper, a platinum wire modified with gold nanoparticles (AuNPs) and reduced graphene oxide (rGO) was used to electrochemically detect dopamine in vivo. Electrochemical performances of microelectrodes (before and after surface modification) were investigated by impedance spectroscopy and cyclic voltammetry. The results showed that AuNPs/rGO composites significantly increase the electrode surface area and improve the electrocatalytic property of platinum wires. The modified electrodes exhibited excellent sensitivity for dopamine detection (LOD=16.57nM), as well as ascendant selectivity (simultaneous detection of ascorbic acid, dopamine, and uric acid), reproducibility (R.S.D.=3.98%), and stability (≫100 repetitive potential sweeps, 1-week lifespan). In vivo experiments showed that the proposed AuNPs/rGO electrode was also capable of detecting dopamine in complex physiological environments, particularly in the striatum of anesthetized rats. Hence, the proposed electrodes provided a potential application in in vivo multiplexing neurotransmitter detection in further research.

Evaluation of a Nanocomposite Based on Reduced Graphene Oxide and Gold Nanoparticles as an Electrochemical Platform for Detection of Sulfamethazine

A nanocomposite based on reduced graphene oxide (rGO) and gold nanoparticles (AuNPs) was synthesized by the microwave-assisted hydrothermal method and applied in the determination of sulfamethazine (SMZ) in swine effluent using a glassy carbon (GC) electrode. The rGO-AuNPs nanocomposite was characterized morphologically, electrochemically and spectrochemically, showing that rGO was modified with the AuNPs. The GC/rGO-AuNPs electrode was optimized for the determination of SMZ, achieving detection limits of 0.1 μmol L−1. The proposed sensor was successfully applied to the determination of SMZ in synthetic swine effluent samples.

Screen printed carbon electrode sensor with thiol graphene quantum dots and gold nanoparticles for voltammetric determination of solatol

This work, a highly selective and sensitive sensor is described for voltammetric determination of the sotalol (SOT). The dual actions of sotalol lead to reductions in the automaticity of myocardial cells and in conduction through the atrioventricular node. Drug analysis has an extensive impact on public health. The molecularly imprinted sensor was constructed by modifying a screen printed carbon electrode (SPCE) with thiol graphene quantum dots (GQD-SH) and gold nanoparticles (AuNPs). Under optimal conditions the nanotools has a dynamic range that covers the 0.1–250 μM SOT concentration range, and the detection limit is 0.035 μM. This is lower than any of the previously reported methods. The MIP-sensor also exhibited excellent selectivity, good stability and adequate reproducibility for the detection of the SOT over its structural analogs. The prepared sensor was successfully applied to the measurement of SOT in various real samples including tablet and human blood serum.

Label-free electrochemical detection of Cloxacillin antibiotic in milk samples based on molecularly imprinted polymer and graphene oxide-gold nanocomposite

Detection of applied antibiotics in food productions could be the first step to avoid future health consequences. The aim of this work was to the synthesis of molecularly imprinted polymer (MIP) particles via non-covalent procedure and evaluation of efficiency MIP for the selective collection of Cloxacillin (CLO) from aqueous and biological samples and consequently quantification of separated CLO using an electrochemical nanosensor. The effect of operational parameters including pH, contact time and MIP dosage for optimization of CLO collection condition were studied. The CLO quantities were determined by a developed electrochemical nanosensor based on a screen-printed electrode modified with graphene oxide and gold nanoparticles. The results showed that the optimum conditions for removal of CLO (92%) were determined at pH = 8.5, with 89 min as contact time and 0.79 g MIP. The linear range was from 110 to 750 nM and the detection limit of the nanosensor was 36 nM. The performance of the MIP-based nanosensor for the spiked Cloxacillin detection in real milk samples showed the potential of the developed nanosensor to be considered in future real sample measurement analysis.

An impedimetric aptasensor for ultrasensitive detection of Penicillin G based on the use of reduced graphene oxide and gold nanoparticles.

The authors describe an impedimetric aptasensor for Penicillin G (PEN) which is an important antibiotic. The method is based on the use of a pencil graphite electrode (PGE) modified with reduced graphene oxide (RGO) and gold nanoparticles (GNPs) for ultrasensitive detection of PEN. The morphology of a bare PGE, RGO/PGE, and GNP/RGO/PGE, and the functional groups on graphene oxide (GO) and RGO were studied using scanning electron microscopy and Fourier transform infrared spectroscopy. Electrochemical impedance spectroscopy was used for detection of PEN by measuring the charge transfer resistance (Rct). Also, cyclic voltammetry was recorded at potential range of 0.30 to +0.70V for PGE treatment. This aptamer-based assay has a wide linear range that extends from 1.0 fM to 10μM, and a limit of detection as low as 0.8 fM. The method was applied to the determination of PEN in spiked milk from cow, sheep, goat and water buffalo. Recoveries ranged from 92% to 104%. The assay is fast, ultrasensitive, high reproducible, and selective over antibiotics such as streptomycin, tetracycline, and sulfadiazine. Graphical abstract Schematic presentation of an impedimetric aptasensor for Penicillin G antibiotic using a pencil graphite electrode (PGE) modified with reduced graphene oxide (RGO) and gold nanoparticles (GNPs). This aptamer based assay has limit of detection as low as 0.8 fM.

Nafion coated Au nanoparticle-graphene quantum dot nanocomposite modified working electrode for voltammetric determination of dopamine

In this work, glassy carbon electrode was modified by Nafion coated gold nanoparticle-graphene quantum dots (Au-GQDs-Nafion) nanocomposite and used for voltammetric determination of trace dopamine. The properties of the as-prepared material were characterized by UV–vis spectrometry, fluorescence spectrometry and TEM. The Au-GQDs-Nafion composite showed the excellent synergistic effect for the electrochemical detection of dopamine (DA). Under optimum conditions, the differential voltammetric (DPV) peak current and the concentration of DA displayed a linear range of 2 μM to 50 μM with the detection limit of 0.84 μM. Furthermore, the as-prepared electrode also showed selectivity toward DA detection in the existence of uric acid (UA) and ascorbic acid (AA). The interference experiment showed, that most of the ions did not show obvious influence on the detection of DA. The modified electrode presented reasonable stability and reproducibility in the voltammetric determination of DA, and also the nanocomposite was applied for the real sample analysis in human urine.

Label-free and ultrasensitive electrochemiluminescence detection of oxidative DNA damage using DNA repair enzyme

Endogenous cell metabolism and chemical reactions can induce oxidative DNA damage, which is involved in the development of different diseases. In this work, a label-free electrochemiluminescence (ECL) assay was proposed for the sensitive detection of oxidative DNA damage in an assembled DNA film. We employed the formamidopyrimidine-DNA glycosylase (Fpg) to convert DNA oxidative nucleobases to strand break, allowing to detect the DNA damage inducing minimal change to the helical structure of DNA. A “light-switch” DNA intercalator, [Ru(bpy)2(dppz)]2+ (bpy = 2, 2′-bipyridine, dppz = dipyrido[3, 2-a:2′, 3′-c]phenazine) was introduced as an ECL signal reporter to detect the DNA strand breaks. The damaged DNA film on the reduced graphene oxide and gold nanoparticles (r-GO@Au) modified ITO electrode bound less ECL indicator than the intact film and accompanied by a drop in ECL intensity, which were also confirmed by gel electrophoresis and fluorescence measurements. As a result, a Fe2+-mediated Fenton reaction with as low as 10 nM Fe2+ and 40 nM H2O2 induced DNA damage can be detected, 100-fold lower than the concentration measured without Fpg. To demonstrate its universality, the successful detection of DNA damage induced by Rose Bengal under irradiation was also achieved. The proposed strategy shows its potential practicality for the sensitive and rapid assessment of the genotoxicity of environmental pollutants.

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.