Nanoparticles Modified Indium Tin Oxide Research Articles

A photoelectrochemical sensor for ultrasensitive dopamine detection based on composites of BiOI and Au-Ag nanoparticles

A photoelectrochemical dopamine sensor based on BiOI and AuAgNPs nanoparticles modified indium tin oxide (ITO) electrode was prepared successfully. The noble metal material AuAg significantly improved the shortcomings of poor surface conductivity and easy recombination of photogenerated electron holes in BiOI. The prepared electrode generated a significantly enhanced and stable photocurrent signal under Xe lamp irradiation. In addition, in weak acidic electrolyte solution, dopamine molecules were protonated and preferent existed in the form of cations, which were easily attracted by electrostatic and adsorbed on the surface of negatively charged AuAgNPs. As an electron donor, DA is vulnerable to oxidation to DA+ by BiOI holes, resulting in an increased anodic photocurrent. The detection limit was 0.3 pM (S/N = 3) and the dopamine concentration exhibited a nice linear relationship between 1 pM and 0.1 μM under ideal circumstances. The dopamine photoelectrochemical sensor shown strong sensitivity, a broad linearity range, and good selectivity against potential uric acid and ascorbic acid interference. This work provides a promising PEC detection platform for the detection of small and medium-sized molecules in biological analysis.

L-Cysteine self-assembled Au(1 1 1)-like nanoparticles modified indium tin oxide electrode for determination of dopamine in the present of uric acid

A novel L-Cysteine self-assembled gold nanoparticles modified indium tin oxide electrode (ITO/Au/L-Cys) was fabricated by facile steps of electro-deposition and immersion in solution. The as-prepared ITO/Au/L-Cys electrode is investigated as a potential electrochemical sensor for dopamine (DA) in the interference of Uric Acid (UA). It combines the catalytic advantages of the Au(111)-like nanoparticles array with self-assembled L-Cysteine. The biosensor displays a highly sensitive and selective behavior for DA in the present of UA. The peak currents response to DA is linear with their concentrations in the range of 2 μM ∼ 400 μM. In addition, a limit of detection reaches up to 0.6 μM (S/N = 3). Consequently, the high sensitivity, stability and excellent biocompatibility of ITO/Au/L-Cys electrode made it as a promising DA sensor.

Construction of iridium oxide nanoparticle modified indium tin oxide electrodes with polycarboxylic acids and pyrophosphoric acid and their application to water oxidation reactions

Nanoparticle-modified electrode surfaces are of fundamental interests for electrochemical and photoelectrochemical applications. By adopting polycarboxylic acids and pyrophosphoric acid as the bridging molecules, iridium oxide nanoparticle modified indium tin oxide (ITO) electrodes are formed. X-ray photoelectron spectroscopy, inductively coupled plasma-mass spectroscopy, and cyclic voltammetry (CV) all confirm the successful modification of the ITO surface. When used to catalyze the water oxidation reaction, the most active electrode (ITO-Ben-IrOx) with the surface coverage of Ir at 3.96 × 10−9 mol cm−2 (estimated by CV) exhibits 194 mV onset overpotentials and 249 mV overpotentials to reach 1 mA cm−2 in 0.1 M HClO4. The turn-over frequency (TOF) for oxygen evolution at 280 mV overpotentials is 1.33 s−1. The electron transfer kinetics of a series of electrodes are investigated, and the results suggest that the electron transfer rate from the electrode substrate to the catalyst does not limit the rate of the water oxidation reaction at low overpotentials, and that the bridging molecules with resonant structures are desirable to enhance the TOF of the water oxidation reaction.

Rapid detection of carbamate pesticide residues using microchip electrophoresis combining amperometric detection

The long-term consumption of food with pesticide residues has harmful effects on human health and the demand for pesticide detection technology tends to be miniaturized and instant. To this end, we demonstrated the first application of indirectly detecting two carbamate pesticides, metolcarb and carbaryl, by gold nanoparticle-modified indium tin oxide electrode in dual-channel microchip electrophoresis and amperometric detection (ME-AD) system. m-Cresol and α-naphthol were obtained after pesticide hydrolysis in alkaline solution, and then separated and detected by ME-AD. Parameters including the detection potential and running buffer concentration and pH were optimized to improve the detection sensitivity and separation efficiency. Under the optimal conditions, the two analytes were completely separated within 80s. m-Cresol and α-naphthol presented a wide linear range from 1 to 100μM, with limits of detection of 0.16μM and 0.34μM, respectively (S/N = 3). Moreover, the reliability of this system was demonstrated by analyzing metolcarb and carbaryl in spiked vegetable samples.

A novel electrochemical non-enzymatic glucose sensor based on Au nanoparticle-modified indium tin oxide electrode and boronate affinity

In this article, a sandwich-type electrochemical sensor for selective determination of glucose based on the formation of glucose-boronic bidentate complex has been developed. 3-aminophenylboronic acid (m-APBA) was immobilized on the gold nanoparticles modified ITO electrode with the linker molecule 4-mercaptobenzoic acid (p-MBA). Then, glucose was captured by boronic acid group from m-APBA as the primary receptor and further grafted with an electroactive ferroceneboronic acid (FcBA) as the secondary receptor to form the sandwich-type sensor for selective detection of glucose. For comprehensively understanding the effect of the charge and structure of the terminal boronic acid group of 3-APBA on its binding to glucose, surface pKa was studied by electrochemical titration method, and it was proved the feasibility of examining glucose in physiological condition by the sandwich-type electrochemical sensor. The electrochemical characteristics of the as-prepared sensor were investigated by using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The electrochemical sensor displayed a linear detection range of glucose from 0.5 mmol L−1 to 30 mmol L−1, with detection limit of 43 µmol L−1. The sensor exhibited good performance in selectivity study with the coexistence of galactose, fructose, mannose and other common interferences in physiological environment, such as, uric acid, ascorbic acid and dopamine. The as-prepared electrode with high sensitivity, good stability and reproducibility as well as excellent biocompatibility made it promising for the development of enzyme-free sensors.

Electrocatalytic oxidation of ethanol and ethylene glycol on bimetallic Ni and Ti nanoparticle-modified indium tin oxide electrode in alkaline solution

Bimetallic Ni and Ti nanoparticle-modified indium tin oxide electrode (Ni–Ti NPs/ITO) were prepared by a two-step ion implantation method, and their electrocatalytic activity toward the oxidation of ethanol and glycol was evaluated. The ion-implantation method is simple, low-cost and environmental friendly without the use of any binder. The Ni–Ti NPs/ITO electrode were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). SEM and AFM showed that the nanoparticles on the Ni–Ti NPs/ITO electrode had a small range of dispersion (10–20 nm) and high dispersion. Electrochemical performances were measured by cyclic voltammetry (CV) and chronoamperometrics. The Ni–Ti NPs/ITO electrode exhibited much higher electrocatalytic activity and stability for ethanol and ethylene glycol oxidation than NiNPs/ITO.

A new photoelectrochemical immunosensor for ultrasensitive assay of prion protein based on hemin-induced photocurrent direction switching

As a significant biomarker of prion diseases, ultrasensitive assay of infectious isoform of prion (PrPSc) is highly desirable for early diagnostics of prion diseases. Herein, taking normal cellular form of prion (PrPC) as a model owing to a high risk of pathogenicity of PrPSc, a new photoelectrochemical immunosensor has been developed based on hemin-induced switching of photocurrent direction. In the presence of PrPC, nitrogen-doped porous carbon-hemin polyhedra labeled with secondary antibody were introduced onto the CdS-chitosan (CS) nanoparticles-modified indium–tin oxide (ITO) electrode via the antigen–antibody specific recognition. Because of the matched energy level between CdS and hemin, the high-efficiency switch of photocurrent direction of the ITO/CdS-CS photoelectrode from anodic to cathodic photocurrent was observed even at very low concentration (0.4 aM) of PrPC. Through changing the specific antibody, this method can be easily expanded to PrPSc assay. Such low detectable limit is very useful in the early diagnosis and screening of prion diseases. The developed method has also promising applications in bioanalysis, disease diagnostics, and clinical biomedicine.

Ultrasensitive cathode photoelectrochemical immunoassay based on TiO2 photoanode-enhanced 3D Cu2O nanowire array photocathode and signal amplification by biocatalytic precipitation

Cathode photoelectrochemical immunoassay usually shows better anti-interference capacity toward real samples than anode photoelectrochemical immunoassay. However, its poor photocurrent response has greatly restricted the detection sensitivity. Herein, a promising ultrasensitive cathode photoelectrochemical immunoassay was developed based on TiO2 photoanode-enhanced 3D Cu2O nanowire array (NWA) photocathode, and coupled with signal amplification by horseradish peroxidase (HRP)-induced biocatalytic precipitation (BCP). Carcinoembryonic antigen (CEA, Ag) was used as a detection model, TiO2 nanoparticle-modified indium tin oxide (ITO) electrode served as the photoanode, and Cu2O NWAs grown in situ on Cu mesh was both the photocathode and photoelectrochemical matrix to immobilize the capture CEA antibodies (Ab1). The signal CEA antibodies (Ab2) were labeled with HRP to form Ab2-HRP bioconjugates, and employed as signal amplifiers when the specific immunoreaction occurred. The developed photoanode-enhanced cathode photoelectrochemical immunoassay has good anti-interference capability, outstanding photocurrent response, and high sensitivity for target Ag detection, which was attributed to the synergistic effects of the 3D nanostructure of Cu2O NWA photocathode, the introduction of TiO2 photoanode as counter electrode, and the signal amplification of Ab2-HRP bioconjugate-induced BCP. The developed cathode photoelectrochemical immunoassay showed a low limit of detection (0.037 pg mL−1) with a wide linear range (from 0.1 pg mL−1 to 50 ng mL−1) for CEA detection.

Photoelectrochemical sensing for hydroquinone based on gold nanoparticle-modified indium tin oxide glass electrode

Gold nanoparticles (GNPs) were deposited directly onto the surface of indium tin oxide (ITO) thin film-coated glass by electrochemical method. It was used as a photoanode in a photoelectrochemical (PEC) cell for sensitive detection of hydroquinone (HQ) at an applied bias potential of 0.15 V vs. saturated calomel electrode. This heterostructure showed dramatically enhanced PEC properties due to the introduction of the Au/ITO interface. Under the irradiation, the marked photocurrent response was observed at the GNPs/ITO photoelectrode compared with bare ITO electrode. The anodic photocurrent could be further largely enhanced by HQ. A new PEC strategy for sensitive detection of HQ at a relative low potential was developed. The linear range for HQ determination was 0.25 to 150 μM, with a detection limit of 0.1 μM. The sensitivity on the GNPs/ITO electrode at the irradiation was ~ 3.3 times higher than that in dark. These results demonstrate that the simple GNPs/ITO electrodes have great potential for PEC analysis application.

A gold nanoparticle-modified indium tin oxide microelectrode for in-channel amperometric detection in dual-channel microchip electrophoresis

A modified indium tin oxide (ITO) microelectrode detector integrated with a dual-channel polydimethylsiloxane (PDMS) microchip is proposed for in-channel amperometric detection in microchip electrophoresis (ME).

Fabrication of nanoporous AuPt nanoparticles modified indium tin oxide electrode and their electrocatalytic effect

This paper describes the synthesis of nanoporous AuPt nanoparticles (np-AuPt NPs) by galvanic replacement reactions that involve large-sized silver nanoparticles (Ag NPs) electrodeposited upon an indium tin oxide (ITO) film glass as a sacrificial template. Compared to a previous synthetic route based on the formation and dealloying of Ag/Au alloy nanoparticles, this method can easily fabricate nanoporous Au nanoparticles (np-Au NPs), as well as nanoporous AuPt nanoparticles. Structural characterization indicated that the products had a particle size of ∼170 nm with a ligament size of tens of nanometers. The fabricated np-Au NPs/ITO and np-AuPt NPs/ITO electrode were also tested and compared for the oxidation of hydrogen peroxide in a phosphate buffer solution (pH 7.0). The np-AuPt NPs/ITO electrode showed a much higher electrocatalytic efficiency and detection sensitivity to hydrogen peroxide than the np-Au NPs/ITO electrode.

Paper–based analytical device for detection of extracellular hydrogen peroxide and its application to evaluate drug–induced apoptosis

Developing cost-effective and simple analysis tools is of vital importance for practical applications in bioanalysis. Here, a disposable paper-based analytical device based on Au nanoparticles modified indium tin oxide electrode has been designed, which was applied for the reliable and non-enzymatic detection of H2O2. Due to the excellent electrocatalytic activity of Au nanoparticles, the disposable electrode exhibited favorable performance toward H2O2 reduction in the linear concentration range from 0.1 to 15μM. The detection limit has been estimated to be 0.08μM, which was lower than certain enzymes and other metal nanomaterials-based sensors. Because of these analytical advantages, the constructed device was used to study the extracellular H2O2 release from NB4 cells and further applied to evaluate sodium selenite induced apoptosis. The results obtained by electrochemical method are correlated well with the results of MTT assays. The developed paper-based sensor is easy-to-fabricate and portable, providing an effective platform for cellular H2O2 sensing and can be used to study the dynamic biological process involving H2O2 in biological and biomedical applications.

A bimetallic Ni–Ti nanoparticle modified indium tin oxide electrode fabricated by the ion implantation method for studying the direct electrocatalytic oxidation of methanol

This study has investigated the oxidation of methanol (CH3OH) on a novel bimetallic Ni–Ti nanoparticle-modified indium tin oxide electrode (Ni–Ti NP/ITO) fabricated by the ion implantation method.

Electrochemical detection of Hg(II) ions based on nanoporous gold nanoparticles modified indium tin oxide electrode

Nanoporous gold nanoparticles (np-Au NPs), dispersed on the indium tin oxide film coated glass, were firstly employed to fabricate Hg(II) sensing platform in differential pulse anodic stripping voltammetry (DPASV). The np-Au NPs integrated the features of highly porous nanoparticles and the high affinity of gold nanomaterials for mercury, which endowed the sensing platform with high sensitivity and good reproducibility. Following optimization of the method, a calibration curve from 0.1 to 10μg/L Hg(II) was obtained in HCl solution. The detection limit was 0.03μg/L (0.15nM) at a signal-to noise ratio of 3. The interference from other heavy metal ions associated with Hg(II) detection could be effectively avoided. The performance of the proposed electrode was also applied in the detection of trace Hg(II) in different real samples with satisfactory results.

A Novel Non‐Enzymatic Glucose Sensor Based on Cobalt Nanoparticles Implantation‐Modified Indium Tin Oxide Electrode

AbstractA new type of cobalt nanoparticles modified indium tin oxide electrode (CoNPs/ITO) was fabricated using ion implantation technique. This method is low‐cost, facile and environmentally friendly without the use of any other chemicals. Electrochemical oxidation of glucose with this sensor was examined by cyclic voltammetry (CV) and chronoamperometry in alkaline aqueous solutions. The proposed sensor exhibited prominent electrocatalytic activity toward the oxidation of glucose with a low limit of detection of 0.25 µM. Furthermore, the fabricated electrode showed excellent selectivity, good reproducibility and long‐term stability. Thus CoNPs/ITO electrode is a promising candidate in the development of non‐enzymatic glucose sensors.

Electrocatalytic oxidation of four low-carbon alcohols at Pd nanoparticle modified indium tin oxide electrode.

A Pd nanoparticle modified indium tin oxide (Pd NPs/ITO) electrode was prepared by cyclic voltammetry (CV) methods. The surface morphology of the modified electrode was characterized by scanning electron microscopy (SEM). The Pd NPs/ITO electrode exhibits excellent electrocatalytic activity towards the oxidation of four low-carbon alcohols including methanol, ethanol, propanol and isopropanol in alkaline electrolyte at room temperature. The effects of reactant concentration and scan rate on the alcohols electrocatalytic oxidation at the Pd NPs/ITO electrode were discussed in detail and the electrocatalytic oxidations of four alcohols are confirmed as diffusion-controlled process from their similar CV characteristic. These low-carbon alcohols or their dissociation products are adsorbed on the surface of Pd NPs/ITO electrode, and simultaneously inhibit the adsorption and desorption of hydrogen, leading to the dominant of alcohol oxidation. The oxidation processes of four low-carbon alcohols are irreversible on Pd NPs/ITO electrode. The activity order of alcohol oxidation on Pd NPs/ITO electrode is identified as ethanol > propanol > methanol > isopropanol. The four alcohols can be easily identified from their positions of oxidation peak.

Label-free detection of folate receptor (+) cells by molecular recognition mediated electrochemiluminescence of CdTe nanoparticles.

Molecular recognition based rapid and simple techniques for identifying subtypes of cancer cells are essential in molecular medicine. In this work, we have designed a molecular recognition mediated electrochemiluminescent (ECL) strategy for label-free and sensitive detection of folate receptor (FR) (+) cells (HeLa cell as a model) on folic acid-functionalized and red emitting CdTe/GSH nanoparticle-modified indium-tin oxide (ITO) electrodes. The ECL emission selectively responses to the rapid binding of FR (+) cells on the modified ITO electrodes due to the block of electron exchange between CdTe nanoparticles and coreacted dissolved oxygen. Microscopic observation verifies that the binding of HeLa cells is more favored than that for HepG2 cells [FR (-) type], resulting in a great difference in ECL intensity. The proposed platform allows the detection of ~35 cells from 10 μL of cell suspension. This study has laid the foundation for building rapid and low-cost ECL diagnostic devices for specific detection of FR (+) cancer cells, with potential applications in profiling of cancer cell subtypes.

Progress in Fabrication and Application of Gold Nanoparticles Modified Indium Tin Oxide Glass

Gold nanoparticles coated on indium tin oxide substrate have been attracting great attention due to their excellent optical, electronic, electrocatalytic and biosensing application in recent years. In this paper, recent research progress in the preparation methods of gold nanoparticles on indium tin oxide substrate surface such as assembling with polymer, seed-mediated growth method and electrodeposition are presented. The applications of gold nanoparticles modified indium tin oxide substrate are also reviewed in electrode, catalyst, sensors and biochemical analysis.

Nonenzymatic glucose sensor based on ITO electrode modified with gold nanoparticles by ion implantation

A novel nonenzymatic glucose sensor, based on gold nanoparticle-modified indium tin oxide electrode (Au/ITO) with ion implantation technique, is presented in this article. Ion implantation method is simple, low-cost and environmental friendly without using any of other chemicals. Through this method, the ITO substrate can be modified by gold nanoparticles (AuNPs) directly. The fabricated electrode was characterized by atomic force microscopy (AFM), X-ray photoelectron spectroscopy analysis (XPS) and cyclic voltammetry (CV). Electrochemical oxidation of glucose with Au/ITO electrode was examined by CV in alkaline aqueous solution. The modified electrode exhibits good electrochemical behavior towards glucose, providing a wide linear range of 1∼170μM and 0.2∼15mM and a low detection limit with 0.4μM. Moreover, this glucose sensor displays acceptable reproducibility and long-term stability. These results indicate that Au/ITO electrode makes it promising for the fabrication of nonenzymatic glucose sensors.

A seed-mediated growth process for the fabrication of a novel gold nanoparticles-attached NH2+ ions implantation-modified indium tin oxide electrode and its electrocatalytic activity

A new type of gold nanoparticles-attached NH2+ ions implantation-modified indium tin oxide electrode (AuNPs/NH2/ITO) was fabricated with a seed-mediated growth method. Amino ion implantation was performed at the energy of 80keV with fluence of 2×1016ionscm−2 for ITO film coated glass, forming the electrode NH2/ITO. The existence of amino groups on the electrode was verified by Fourier transform infrared (FT-IR) spectrometry and X-ray photoelectron spectra (XPS). The attachment of AuNPs onto the surface of the NH2/ITO electrode was exhibited by using the scanning electron microscopy (SEM). Comparing with the gold nanoparticles modified indium tin oxide (AuNPs/ITO), we found that ion implantation approach provided a useful strategy to attach AuNPs on the NH2/ITO surface with higher density. Cyclic voltammetric results indicated that the AuNPs/NH2/ITO electrode showed excellent electrochemical properties and electrocatalytic effects toward some small biomolecules such as uric acid. The current response was increased linearly with increasing uric acid concentration in the range of 1.6×10−5M to 2.6×10−4M and the detection limit was found to be 4.8×10−6M (S/N=3). Thus this material is expected to have widely potential applications in electrochemical analysis and biosensors.