Nanoparticle-decorated Graphene Oxide Research Articles

Preparation and Tribological Properties of Lanthanum Trifluoride Nanoparticles-Decorated Graphene Oxide Nanosheets

Graphene oxide (GO) nanosheets were decorated with lanthanum trifluoride (LaF3) nanoparticles by a simple solution method to afford LaF3–GO nanohybrids, with which ammonium fluoride and lanthanum nitrate were used as raw materials to synthesize LaF3 nanoparticles. As-prepared LaF3–GO nanohybrids were characterized by X-ray diffraction, Raman spectrometry, transmission electron microscopy, and Fourier transform infrared spectrometry. Moreover, the thermal stability of the as-prepared LaF3–GO nanohybrids was evaluated by thermogravimetric analysis, and their tribological properties as an additive of distilled water were evaluated with a four-ball friction and wear tester. It was found that LaF3 nanoparticles are integrated with the GO nanosheets through electrostatic interaction thereby affording LaF3–GO nanohybrids. In addition, when the as-prepared LaF3–GO nanohybrid was added into distilled water at an optimum mass fraction of 1.5%, it was able to significantly improve the tribological properties of distilled water. This is because LaF3–GO nanohybrids can be deposited on rubbed steel surfaces to form protective and lubricious layers consisting of GO, LaF3, Fe2O3, and FeF3, thereby significantly reducing the friction and wear of the steel–steel contact under water lubrication.

An ultrasensitive sandwich type electrochemiluminescence immunosensor for triiodothyronine detection using silver nanoparticle-decorated graphene oxide as a nanocarrier.

An ultrasensitive electrochemiluminescence (ECL) immunosensor was constructed to detect 3,3',5-triiodothyronine (T3). The system employed T3-conjugated, silver nanoparticle-decorated carboxylic graphene oxide (Ag@fGO-T3) as a carrier and anti-T3 antibody-tris(2,2'-bipyridyl) ruthenium(II) (Ru(bpy)3(2+)) as a probe. The Ag@fGO-T3 and Ru(bpy)3(2+) complex could be mobilized rapidly to the anode in the reaction chamber through electrophoresis. The fGO is reduced electrochemically at the electrode, and the electrons could transfer from an anode to the Ru(bpy)3(2+). The complex is excited at the electrode and an ECL signal is produced upon reacting with tripropylamine (TPrA). Because of its large surface area and excellent conductivity, Ag@fGO could enhance ECL signal significantly in the system. Quantitative measurement of T3 could be achieved in the range from 0.1 pg/mL to 0.8 ng/mL with a detection limit of 0.05 pg/mL. In addition, the novel immunosensor showed good specificity in the presence of serum, indicating its high potential in clinical use.

Preparation, characterization, and antibacterial activity of silver nanoparticle-decorated graphene oxide nanocomposite.

In this work, we report a facile and green approach to prepare a uniform silver nanoparticles (AgNPs) decorated graphene oxide (GO) nanocomposite (GO-Ag). The nanocomposite was fully characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectra, ultraviolet-visible (UV-vis) absorption spectra, and X-ray photoelectron spectroscopy (XPS), which demonstrated that AgNPs with a diameter of approximately 22 nm were uniformly and compactly deposited on GO. To investigate the silver ion release behaviors, HEPES buffers with different pH (5.5, 7, and 8.5) were selected and the mechanism of release actions was discussed in detail. The cytotoxicity of GO-Ag nanocomposite was also studied using HEK 293 cells. GO-Ag nanocomposite displayed good cytocompatibility. Furthermore, the antibacterial properties of GO-Ag nanocomposite were studied using Gram-negative E. coli ATCC 25922 and Gram-positive S. aureus ATCC 6538 by both the plate count method and disk diffusion method. The nanocomposite showed excellent antibacterial activity. These results demonstrated that GO-Ag nanocomposite, as a kind of antibacterial material, had a great promise for application in a wide range of biomedical applications.

Removal of Pb(II) using silver nanoparticles deposited graphene oxide: equilibrium and kinetic studies

Silver nanoparticles-decorated graphene oxide (Ag-GO) composites as advanced metal ion adsorbents have been synthesized. The silver nanoparticles (Ag-NPs) were homogeneously deposited onto graphene oxide (GO) surface by an optimal method, in which N,N-dimethylformamide as a co-dispersant is added to an aqueous suspension of GO and AgNO3. The Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy indicates that GO and Ag-GO are fully exfoliated. The synthesized Ag-GO NPs were used for removal of Pb(II) metal ions. The experiments showed that the removal of metal ions followed a pseudo-second-order kinetic model and equilibrium adsorption studies confirmed that the Langmuir model provided a better fit than others as revealed by high correlation coefficients and low Chi-square values. These Ag-GO NPs can be successfully used for the separation of Pb(II) from aqueous solutions.

Detection of cellular H2O2 in living cells based on horseradish peroxidase at the interface of Au nanoparticles decorated graphene oxide

An interface of graphene oxide (GO) decorated with Au nanoparticles (AuNPs) was fabricated to immobilize horseradish peroxidase (HRP) for amperometric detection of H2O2. Due to the biocompatibility of AuNPs and large surface area of GO, the immobilized HRP could retain its inherent bioactivity and exhibited remarkable performance for H2O2 detection. These remarkable analytical advantages such as low detection limit, wide linear range and fast response time could fulfill the requirement of real-time measurement of cellular H2O2 in living cells. Interestingly, results indicated that the levels of intracellular H2O2 depended on the types of cells. This approach provided a simple and effective platform for sensing H2O2 inside biological cells and could be used for the study of H2O2-involved dynamic biological processes.

Highly sensitive non-enzymatic glucose sensor based on Pt nanoparticle decorated graphene oxide hydrogel

Highly sensitive non-enzymatic glucose sensors composed of Pt nanoparticles and a 3D graphene hydrogel (GOH) were fabricated by a one-step hydrothermal synthesis. The Pt nanoparticles acted not only as electrocatalysts to oxidize glucose but also as spacers that prevent the agglomeration of graphene sheets and increase the surface area of GOHs. The Pt/GOH glucose sensor fabricated in the presence of 15mg chloroplatinic acid (HPt) exhibited a surface area of 508m2g−1 and cyclic voltammetry revealed a glucose sensitivity of 137.4μAmM−1cm−2, which is 7-fold higher than the undecorated GOH. An excess of Pt resulted in a decrease in glucose sensitivity due to the loss of surface area and electrocatalytic active area by the agglomeration of Pt particles. Pt/GOH showed good response toward real blood samples and was also not affected by ascorbic acid (AA), uric acid (UA) and dopamine (DA) which are common interfering species.

A sensitive molecular imprinted electrochemical sensor based on gold nanoparticles decorated graphene oxide: Application to selective determination of tyrosine in milk

In present study, a sensitive imprinted electrochemical sensor based on cubic gold nanoparticles (cAuNPs) involved in 2-aminoethanethiol (2-AET) functionalized graphene oxide (GO) modified glassy carbon (GC) electrode was developed for determination of tyrosine (Tyr). The prepared nanomaterials were characterized by using scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and reflection–absorption infrared spectroscopy (RAIRS). Tyr imprinted film was constructed by cyclic voltammetry (CV) for 20 cycles in the presence of 80mM phenol in phosphate buffer solution (pH 7.0) containing 20mM Tyr. The imprinted electrochemical sensor was validated according to the ICH guideline and found to be linear, sensitive, precise and accurate. The linearity range and the detection limit were obtained as 1.0×10−9 to 2.0×10−8M and 1.5×10−10M, respectively. The developed imprinted sensor was successfully applied to milk samples. In addition, the stability and reproducibility of the prepared molecular imprinted electrode were investigated. The excellent long-term stability and reproducibility of the prepared Tyr imprinted electrodes make them attractive in electrochemical sensors.

Au nanoparticle decorated graphene oxide as a novel coating for solid-phase microextraction

A novel solid-phase microextraction (SPME) fiber based on a stainless steel wire coated with Au nanoparticle decorated graphene oxide was prepared using a novel protocol.

Facile synthesis of silver nanoparticle-decorated graphene oxide nanocomposites and their application for electrochemical sensing

TWEEN 80 was employed as the reducing agent, stabilizer and modifier in the synthesis of nanoparticle–graphene oxide nanocomposites.

Functional nanoparticle-decorated graphene oxide sheets as stabilizers for Pickering high internal phase emulsions and graphene oxide based foam monoliths

A facile and versatile approach was developed for the preparation of graphene oxide sheet-based Pickering high internal phase emulsions by nanoparticle decoration.

Graphene oxide shell-isolated Ag nanoparticles for surface-enhanced Raman scattering

An efficient surface enhanced Raman scattering (SERS) substrate has been developed based on Ag nanoparticle-decorated graphene oxide (GO). The structure of Ag@GO hybrid material was confirmed by X-ray diffraction, transmission and scanning electron microscopy. The as-prepared substrate exhibited the enhancement ability of SERS toward various aromatic dyes, such as Rhodamine 6G, Rhodamine B, and crystal violet. The enhanced Raman signals could be due to the presence of an ultrathin GO shell with 2.8nm in thickness. In particular, the GO shell could efficient to maintain chemical and optical stability, and improved biocompatibility for this SERS-activity material.

Synergistic effect of Ag nanoparticle-decorated graphene oxide and carbon fiber on electrical actuation of polymeric shape memory nanocomposites

This study reports an effective approach of significantly improving electrical properties and recovery performance of shape memory polymer (SMP) nanocomposite, of which its shape recovery was triggered by electrically resistive Joule heating. Reduced graphene oxide (GOs) self-assembled and grafted onto carbon fiber, were used to enhance the interfacial bonding with the SMP matrix via van der Waals force and covalent bond, respectively. A layer of Ag nanoparticles was synthesized from Ag+ solution and chemically deposited onto GO assemblies. These Ag nanoparticles were expected to bridge the gap between GO and improve the electrical conductivity. The experimental results reveal that the electrical conductivity of the SMP nanocomposite was significantly improved via the synergistic effect between Ag nanoparticle-decorated GO and carbon fiber. Finally, the electrically induced shape memory effect of the SMP nanocomposite was achieved, and the temperature distribution in the SMP nanocomposites was recorded and monitored. An effective approach was demonstrated to produce the electro-activated SMP nanocomposites and the resistive Joule heating was viable at a low electrical voltage below 10 V.

Amperometric detection of Sudan I in red chili powder samples using Ag nanoparticles decorated graphene oxide modified glassy carbon electrode

A simple and sensitive electrochemical method was developed to determine the concentration of Sudan I in chili powder based on silver nanoparticles decorated graphene oxide modified glassy carbon electrode (AgNPs@GO/GCE). The voltammetry behaviour of Sudan I on modified GCE was investigated in phosphate buffer medium (PBS) with various pH ranges and the electron transfer properties were studied. It is found that the AgNPs@GO/GCE can catalyse the reduction of azo group, NN followed by electrochemical oxidation of -OH group present in Sudan I dye molecule. Quantitative detection of Sudan I present in food products was carried out by amperometry method in which reduction potential was fixed at −0.77V vs. Ag/AgCl. The amperometry method showed an excellent performance with a sensitivity of 6.83μAmM−1 and a detection limit of 11.4×10−7ML−1. A linear calibration graph was constructed in the ranging 3.90×10−6 to 3.19×10−5ML−1. The method was successfully applied for the determination of Sudan I in red chili powder samples.

Single Step Synthesis of Gold Nanoparticles Decorated Graphene Oxide Using Aniline as Reducing Agent and Study its Application on Elecrocatalytic Detection of Tryptophan

A single step method for the synthesis of gold nanoparticles decorated graphene oxide nanocomposite using aniline as reducing agent has been developed. The composite was characterized using FE-SEM, UV-Vis and FT-IR and XRD analysis. The electron transfer behavior of the modified electrodes was investigated in a redox probe using cyclic voltammetry. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were employed to evaluate the electrochemical properties of AuNPs/GO/GCE towards the electrochemical oxidation of tryptophan. A calibration graph was constructed by plotting the concentration of tryptophan against the peak current. Under the optimum experimental conditions, the oxidation peak currents were measured by varying the tryptophan concentrations. The resulting sensor displays an excellent repeatability and long-term stability.

Multifunctional PEG-GO/CuS nanocomposites for near-infrared chemo-photothermal therapy

The synergistic therapy, the combination of photothermal therapy and chemotherapy, has become a potential treatment in the battles with cancer. Here, we developed a synergistic therapy tool that based on CuS nanoparticles-decorated graphene oxide functionalized with polyethylene glycol (PEG-GO/CuS) for cervical cancer treatment. The as-synthesized PEG-GO/CuS nanocomposites with excellent biocompatibility was revealed to have high storage capacity for anticancer drug of doxorubicin (Dox) and high photothermal conversion efficiency, and were effectively employed for the ablation of tumor. In addition, the therapeutic efficacy of Dox-loaded PEG-GO/CuS (PEG-GO/CuS/Dox) nanocomposites was evaluated in vitro and in vivo for cervical cancer therapy. In vitro cell cytotoxicity tests of PEG-GO/CuS/Dox demonstrate about 1.3 and 2.7-fold toxicity than PEG-GO/CuS and free Dox under 5 min irradiation with NIR laser at 1.0 W/cm2, owing to both PEG-GO/CuS-mediated photothermal ablation and cytotoxicity of light-triggered Dox release. In mouse models, mouse cervical tumor growth was found to be significantly inhibited by the chemo-photothermal effect of PEG-GO/CuS/Dox nanocomposites, resulting in effective tumor reduction. Overall, compared with chemotherapy or photothermal therapy alone, the combined treatment demonstrates better therapeutic efficacy of cancer in vitro and in vivo. These findings highlight the promise of the highly versatile multifunctional nanoparticles in biomedical application.

A novel and sensitive electrochemical DNA biosensor based on Fe@Au nanoparticles decorated graphene oxide

A novel and sensitive electrochemical biosensor for selective determination of DNA was developed based on Fe@Au nanoparticles (Fe@AuNPs) involving 2-aminoethanethiol (AET) functionalized graphene oxide (GO) (Fe@AuNPs-AETGO). Firstly, 5′-TA CCG GGT GCT CGA GCT-(CH2)3-SH-3′ single-stranded probe (ss-DNA) was immobilized on Fe@AuNPs-AETGO nanocomposite to form ssDNA-Fe@AuNPs-AETGO. Square wave voltammetry (SWV) was applied to monitor the DNA hybridization by basic blue 41 (BB41) as an electrochemical indicator. The DNA immobilization and hybridization on the film were studied by cyclic voltammetry (CV), SWV and electrochemical impedance spectroscopy (EIS). Under optimum conditions, the peak currents of BB41 were linear with the logarithm of the concentrations of complementary DNA (5′-AT GGC CCA CGA GCT CGA-(CH2)3-SH-3) from 1.0×10−14 to 1.0×10−8M with a detection limit of 2.0×10−15M. The biosensor also showed high selectivity to one-base, two-base and three-base mismatched DNA. Compared with the other electrochemical DNA biosensors, the proposed biosensor showed its own performance of simplicity, good stability and high sensitivity.

Green synthesis of gold nanoparticle–decorated graphene oxides that enhance the photocurrent in polymer solar cells

ABSTRACTMetal nanoparticle–decorated graphene oxides are promising materials for use in various optoelectronic applications because of their unique plasmonic properties. In this paper, a simple, environmentally friendly method for the synthesis of gold nanoparticle–decorated graphene oxide that can be used to improve the efficiency of organic photovoltaic devices (OPVs) is reported. Here, the amino acid glycine is empolyed as an environmentally friendly reducing reagent for the reduction of gold ions in the graphene oxide solutions. Furthermore, these nanocomposites are empolyed as the anode buffer layer in OPVs to trigger surface plasmonic resonance, which improved the efficiency of the OPVs. The results indicate that such nanomaterials appear to have great potential for application in OPVs.

Gold nanoparticle-decorated graphene oxides for plasmonic-enhanced polymer photovoltaic devices

In this work, gold nanoparticle/graphene oxide (AuNP/GO) nanocomposites are synthesized and used as anodic buffer layers in organic photovoltaic devices (OPVs). The application of thiol-terminated polyethylene glycol as a capping agent prevents the aggregation of AuNPs on the GO surface and further improves the solubility and stability of these nanomaterials in solutions. When AuNP/GO nanomaterials served as the buffer layers, they introduced localized surface plasmon resonance (LSPR) in the OPVs, leading to noticeable enhancements in the photocurrent and the efficiencies of the OPVs. We attribute the primary origin of the improvement in device performance to local field enhancement induced by the LSPR. We anticipate that this study might open up new avenues for constructing plasmon-enhancing layers on the nanoscale to improve the performance of solar cells.

Green synthesis of dimension-controlled silver nanoparticle–graphene oxide with in situ ultrasonication

A green chemical approach to control the dimensions of Ag nanoparticle-decorated graphene oxide (AgNP–GO) composites was proposed by in situ ultrasonication of a mixture of AgNO3 and GO solution with the assistance of vitamin C acting as an environmentally friendly reducing agent at room temperature. The AgNP–GO composites were characterized by X-ray diffraction, transmission electron microscopy, energy-dispersive spectroscopy, Fourier transform infrared spectroscopy, Raman spectra and ultraviolet–visible absorption spectra. The results demonstrated that Ag nanoparticles with an average diameter of ∼15nm were uniformly dispersed on the surface of GO nanosheets by in situ ultrasonication of 1min with vitamin C. Increasing the ultrasonication times resulted in Ag nanoparticles with tunable dimensions ranging from 15 to 55nm being formed on the surface of GO nanosheets. The amount of silver nitrate and the ultrasonication time play a key role in the control of the dimension of Ag nanoparticles on GO, and a formation mechanism of the as-prepared AgNP–GO composites is proposed. This study provides a guide to controlling the dimensions of AgNP–GO composites, which may hold promise as advanced materials for various analytical applications such as catalysis, sensors and microchips.

Size-dependent work function and catalytic performance of gold nanoparticles decorated graphene oxide sheets

We investigated the size-dependent work function and catalytic performance of gold nanoparticles (AuNPs) decorated graphene oxide (GO). The ultraviolet photoelectron spectroscopic analysis revealed that the work function decreased from 5.76 to 5.35eV as the AuNP size was reduced from 40 to 5nm. The catalytic performance of GO:AuNP hybrids was evaluated from the reduction of o-nitroaniline to 1,2-benzenediamine using sodium borohydride as a reducing agent. A considerable increase of the reaction rate constant with decreasing AuNP size is due to the enhanced surface interaction of AuNPs. Improved o-nitroaniline adsorption and electron transfer at the Au/GO interface leads to better catalytic activity, and this is more noticeable at an AuNP size of 5nm. Our result indicates that GO:AuNP hybrids have considerable potential for use in industry wastewater treatment.