Multifunctional Graphene Oxide Research Articles

Graphene Oxide/Chitosan Aerogel Microspheres with Honeycomb-Cobweb and Radially Oriented Microchannel Structures for Broad-Spectrum and Rapid Adsorption of Water Contaminants.

Multifunctional graphene oxide (GO)/chitosan (CS) aerogel microspheres (GCAMs) with honeycomb-cobweb and radially oriented microchannel structures are prepared by combining electrospraying with freeze-casting to optimize adsorption performances of heavy metal ions and soluble organic pollutants. The GCAMs exhibit superior adsorption capacities of heavy metal ions of Pb(II), Cu(II), and Cr(VI), cationic dyes of methylene blue (MB) and Rhodamine B, anionic dyes of methyl orange and Eosin Y, and phenol. It takes only 5 min to reach 82 and 89% of equilibrium adsorption capacities for Cr(VI) (292.8 mg g-1) and MB (584.6 mg g-1), respectively, much shorter than the adsorption equilibrium time (75 h) of a GO/CS monolith. More importantly, the GCAMs maintain excellent adsorption capacity for six cycles of adsorption-desorption. The broad-spectrum, rapid, and reusable adsorption performance makes the GCAMs promising for highly efficient water treatments.

Faraday Cage-Type Electrochemiluminescence Biosensor Based on Multi-Functionalized Graphene Oxide for Ultrasensitive Detection of MicroRNA-21

A Faraday cage-type electrochemiluminescence (ECL) biosensor for ultrasensitive detection of cancer-associated microRNA-21 was constructed based on Fe3O4@Au magnetic nanoparticles (Fe3O4@Au MNPs) and multi-functionalized graphene oxide. The capture unit (Fe3O4@Au MNPs-cDNA) was prepared by immobilizing capture DNA (cDNA) on Fe3O4@Au MNPs, while the multi-functionalized graphene oxide acted as the signal unit ((sDNA&luminol)@GO). In this biosensor, the capture unit, which was used to catch the microRNA-21, could be easily attracted onto the magnetic glassy carbon electrode surface. After the hybridization of microRNA-21 with the capture unit, the signal unit was further hybridized to form a Faraday cage-type structure, in which the signal unit was directly fixed onto the electrode surface, resembling a huge net and even becoming a part of the electrode surface. All luminol molecules labeled on the signal unit could take part in the electrode reaction, thus greatly enhancing the ECL signal. The ECL intensity was found to increase with the logarithm of microRNA-21 concentrations from 1 fM to 10 pM with a detection limit of 0.3 fM. In addition, this proposed Faraday cage-type ECL biosensor can be used for practical analysis of microRNA-21 in human serum, providing an ultrasensitive detection platform for microRNAs in clinical diagnosis.

Synergistic antiviral effect of curcumin functionalized graphene oxide against respiratory syncytial virus infection.

The diseases attributable to viruses remain a global burden. The respiratory syncytial virus (RSV), which is considered as the major viral pathogen of the lower respiratory tract of infants, has been implicated in severe lung disease. In this contribution, we developed a β-cyclodextrin (CD) functionalized graphene oxide (GO) composite, which displayed excellent antiviral activity and could load curcumin efficiently. RSV, a negative-sense single-stranded enveloped RNA virus, was employed as a model virus to investigate the antiviral activity of multifunctional GO. Proved by the tissue culture infectious dose assay and immunofluorescence assay, the curcumin loaded functional GO was confirmed with highly efficient inhibition for RSV infection and great biocompatibility to the host cells. The results showed that the composite could prevent RSV from infecting the host cells by directly inactivating the virus and inhibiting the viral attachment, and possessed prophylactic and therapeutic effects towards the virus. Our data indicate that the composite may provide new insights into antiviral therapy for RSV infection.

Multifunctional graphene oxide for bioimaging: emphasis on biological research

AbstractGraphene oxide (GO) nanomaterials offer a wide range of bioimaging applicability. Almost complete quenching ability of fluorescence by GO and natural interaction of GO with single stranded nucleic acid made GO a useful and intriguing multifunctional nanoplatform both as a biosensor for in vitro microplate diagnostics and as a drug delivery carrier for targeted delivery. GO’s large surface area and strong near infrared absorbance contribute to enhancement of a therapeutic effect with abundant loading of drugs for possible photothermal and photodynamic therapy. Bioimaging capability of GO made it a good theranostic tool, while enabling tracing in vivo pharmacokinetics during concurrent treatment. Fluorescence, either signal on or off, Raman and surface-enhanced Raman scattering (SERs), photoacoustic, and radionuclide imaging modalities can be used for theranostic purposes using GO nanomaterials. In this review, we highlight current applications of GO for bioimaging that are classified into in vitro microplate, in vitro cellular and in vivo bioimaging.

Synergistic effect on the mechanical behaviors of ternary graphene oxide-zirconium diboride-poly(vinyl alcohol) papers

Through design hierarchical architectures and interlayer interaction, multifunctional macroscopic graphene oxide papers tend to attain outstanding mechanical properties. Three dimensional architectures functionalized graphene oxide papers are self-assembled with zirconium diboride particles and poly(vinyl alcohol, PVA) using vacuum assisted filtration method. Firstly, ternary graphene oxide micro-scale structures are achieved by the addition of zirconium diboride particles. Then, PVA is introduced to enhance the interface interaction between graphene oxide nanosheets and zirconium diboride particles. The results show significant enhancements in fracture strength (~200%) and tensile modulus (20–100%) are attained through synergistic effect of ternary graphene oxide structures and interlayer interaction between PVA, graphene oxide and zirconium diboride particles.

Prostate cancer targeted multifunctionalized graphene oxide for magnetic resonance imaging and drug delivery

Dendrimers capped with amino groups (DEN) are grafted to graphene oxide (GO) nanosheets for subsequent functionalization of GO with gadolinium diethylene triamine pentaacetate (Gd-DTPA) and prostate stem cell antigen (PSCA) monoclonal antibody (mAb). The as-prepared GO-DEN(Gd-DTPA)-mAb exhibits very low cytotoxicity, negligible hemolytic activity, and no perceptible toxic effects in mice. GO-DEN(Gd-DTPA)-mAb can specifically target PSCA over-expressed cancer cells to give a significant T1-weighted contrast enhancement effect. The in vivo magnetic resonance imaging results indicate that GO-DEN(Gd-DTPA)-mAb can be used as a targeted contrast agent for prostate tumor imaging. GO-DEN(Gd-DTPA)-mAb can be efficiently loaded with doxorubicin hydrochloride (DOX), and the resulting GO-DEN(Gd-DTPA)-mAb/DOX exhibits enhanced cytotoxicity to PC-3 cells due to good targeting performance. By following the PC-3 tumor growth in mouse model after intravenous administration of GO-DEN(Gd-DTPA)-mAb/DOX, it is demonstrated that GO-DEN(Gd-DTPA)-mAb can targetedly deliver anticancer drugs to malignant prostate tumors and inhibit tumor growth.

Multi-functionalized graphene oxide complex as a plasmid delivery system for targeting hepatocellular carcinoma therapy

A novel and efficient graphene-based gene delivery vector was prepared, the effect of changing the PEI content on the size, stability and transfection efficiency were investigated.

Targeted delivery and controlled release of doxorubicin into cancer cells using a multifunctional graphene oxide

We have synthesized a new multifunctional graphene oxide as a drug carrier targeting to hepatocarcinoma cells. Surface modified graphene oxide with polyethyleneimine (PEI) sequentially derivatised with fluorescein isothiocyanate (FI) and polyethylene glycol (PEG)-linked lactobionic acid (LA), and acetylation of remaining terminal amines of the PEI produced a new multifunctional graphene oxide drug carrier (GO/PEI.Ac-FI-PEG-LA). Doxorubicin (DOX), an anticancer drug, was encapsulated in GO/PEI.Ac-FI-PEG-LA to give GO/PEI.Ac-FI-PEG-LA/DOX, with a drug loading percentage of 85%. We showed that both GO/PEI.Ac-FI-PEG-LA and GO/PEI.Ac-FI-PEG-LA/DOX were water soluble and stable between pH 5.0 and 9.0. In vitro release studies indicated that the release rate of DOX from GO/PEI.Ac-FI-PEG-LA/DOX complexes were significantly higher at pH5.8 than that of the physiological pH. Another important feature of this carrier is its good cell viability in the tested concentration range (0‐4μM), and the GO/PEI.Ac-FI-PEG-LA/DOX can specifically target cancer cells overexpressing asialoglycoprotein (ASGPR) receptors and exert growth inhibition effect to the cancer cells. The enhanced target specificity and the substantial improvement in pH responsive controlled release have made this new carrier a potential choice for non-covalent encapsulation of drugs in GO, and a delivery system for cancer therapy.

A label-free multi-functionalized graphene oxide based electrochemiluminscence immunosensor for ultrasensitive and rapid detection of Vibrio parahaemolyticus in seawater and seafood

A label-free electrochemiluminescence (ECL) immunosensor for ultrasensitive and rapid detection of marine pathogenic bacterium Vibrio parahaemolyticus (VP) in seawater and seafood was developed based on multi-functionalized graphene oxide, which was prepared with N-(4-aminobutyl)-N-ethylisoluminol (ABEI) and VP antibody (anti-VP) simultaneously immobilized on the surface of magnetic graphene oxide (nanoFe3O4@GO). ABEI and anti-VP acted as the electrochemiluminophore and the capture device for VP respectively. Good conductivity and two-dimensional structure of the nanoFe3O4@GO enabled all the ABEI, immobilized on GO, electrochemically active and thus improved the detection sensitivity. Under optimal conditions, the ECL intensity decreased with increasing logarithmic concentrations of VP in the range of 10–108CFU/mL, with a detection limit of 5CFU/mL for seawater and 5CFU/g for seafood. This ECL immunosensor showed high specificity, stability and reproducibility for the detection of VP. In addition, the ECL immunosensor has been successfully used to determine the concentration of VP in seawater and seafood rapidly, with a recovery of 94.4–112.0% and RSD 4.1–11.7%. Therefore, the developed immunosensor shows great prospect for practical application.

One-pot synthesized multi-functional graphene oxide as a water-tolerant and efficient metal-free heterogeneous catalyst for cycloaddition reaction

A series of functional graphene oxide (F-GO) materials were prepared by silylanization of graphene oxide (GO) with chlorine-terminal silanes and subsequent nucleophilic substitution reaction with tertiary amine in a one-pot approach. The quaternary ammonium salt was generated and immobilized simultaneously in situ, and the primary amine is beneficial to improve the number of surface functionalities on GO. This is the first time that a multi-functional GO material was designed, prepared and used for the synthesis of cyclic carbonates through the cycloaddition of carbon dioxide (CO2) to epoxides. The F-GO catalyst can be easily separated and reused for at least five times without significant loss of activity (TOF=46.4h−1). The excellent performance is attributed to the synergetic effect of silanol group and halide anion for ring opening of epoxide as well as the role of amine for CO2 adsorption and activation. A possible mechanism is proposed for the cycloaddition reaction over F-GO.

Multifunctional biocompatible graphene oxide quantum dots decorated magnetic nanoplatform for efficient capture and two-photon imaging of rare tumor cells.

Circulating tumor cells (CTCs) are extremely rare cells in blood containing billions of other cells. The selective capture and identification of rare cells with sufficient sensitivity is a real challenge. Driven by this need, this manuscript reports the development of a multifunctional biocompatible graphene oxide quantum dots (GOQDs) coated, high-luminescence magnetic nanoplatform for the selective separation and diagnosis of Glypican-3 (GPC3)-expressed Hep G2 liver cancer tumor CTCs from infected blood. Experimental data show that an anti-GPC3-antibody-attached multifunctional nanoplatform can be used for selective Hep G2 hepatocellular carcinoma tumor cell separation from infected blood containing 10 tumor cells/mL of blood in a 15 mL sample. Reported data indicate that, because of an extremely high two-photon absorption cross section (40530 GM), an anti-GPC3-antibody-attached GOQDs-coated magnetic nanoplatform can be used as a two-photon luminescence platform for selective and very bright imaging of a Hep G2 tumor cell in a biological transparency window using 960 nm light. Experimental results with nontargeted GPC3(−) and SK-BR-3 breast cancer cells show that multifunctional-nanoplatform-based cell separation, followed by two-photon imaging, is highly selective for Hep G2 hepatocellular carcinoma tumor cells.

A one-step electrochemiluminescence immunosensor preparation for ultrasensitive detection of carbohydrate antigen 19-9 based on multi-functionalized graphene oxide

A one-step electrochemiluminescence (ECL) immunosensor for ultrasensitive detection of carbohydrate antigen 19-9 (CA19-9) was developed based on multi-functionalized graphene oxide (GO), which was prepared with N-(4-aminobutyl)-N-ethylisoluminol (ABEI) and CA19-9 antibody (anti-CA19-9) chemically bound to the surface of magnetic GO (nanoFe3O4@GO). ABEI and anti-CA19-9 acted as the electrochemiluminophore and the capture device for CA19-9 respectively. NanoFe3O4@GO enabled all the ABEI immobilized molecules electrochemically active due to its good conductivity, and brought multi-functionalized GO attracted on the surface of magnetic glass carbon electrode through magnetism. Thus the ECL immunosensor could be prepared through a one-step process that facilitates ultrasensitive detection of CA19-9. Under optimal conditions, the ECL intensity of the immunosensor decreased proportionally to the logarithmic concentrations of CA19-9 in the range of 0.001–5U/mL with a detection limit of 0.0005U/mL. This one-step ECL immunosensor showed good performance in specificity, stability, reproducibility, regeneration and application. It opened a new avenue to apply multi-functionalized bionanomaterials in ECL immunoassay.

Graphene Oxide: Ultrafast Fabrication of Covalently Cross‐linked Multifunctional Graphene Oxide Monoliths (Adv. Funct. Mater. 31/2014)

Graphene Oxide: Ultrafast Fabrication of Covalently Cross‐linked Multifunctional Graphene Oxide Monoliths (Adv. Funct. Mater. 31/2014)

Ultrafast Fabrication of Covalently Cross‐linked Multifunctional Graphene Oxide Monoliths

Stable graphene oxide monoliths (GOMs) have been fabricated by exploiting epoxy groups on the surface of graphene oxide (GO) in a ring opening reaction with amine groups of poly(oxypropylene) diamines (D400). This method can rapidly form covalently bonded GOM with D400 within 60 s. FTIR and XPS analyses confirm the formation of covalent C‐N bonds. Investigation of the GOM formation mechanism reveals that the interaction of GO with a diamine cross‐linker can result in 3 different GO assemblies depending on the ratio of D400 to GO, which have been proven both by experiment and molecular dynamics calculations. Moreover, XRD results indicate that the interspacial distance between GO sheets can be tuned by varying the diamine chain length and concentration. We demonstrate that the resulting GOM can be moulded into various shapes and behaves like an elastic hydrogel. The fabricated GOM is non‐cyctotoxic to L929 cell lines indicating a potential for biomedical applications. It could also be readily converted to graphene monolith upon thermal treatment. This new rapid and facile method to prepare covalently cross‐linked GOM may open the door to the synthesis and application of next generation multifunctional 3D graphene structures.

High-Performance Multifunctional Graphene Yarns: Toward Wearable All-Carbon Energy Storage Textiles

The successful commercialization of smart wearable garments is hindered by the lack of fully integrated carbon-based energy storage devices into smart wearables. Since electrodes are the active components that determine the performance of energy storage systems, it is important to rationally design and engineer hierarchical architectures atboth the nano- and macroscale that can enjoy all of the necessary requirements for a perfect electrode. Here we demonstrate a large-scale flexible fabrication of highly porous high-performance multifunctional graphene oxide (GO) and rGO fibers and yarns by taking advantage of the intrinsic soft self-assembly behavior of ultralarge graphene oxide liquid crystalline dispersions. The produced yarns, which are the only practical form of these architectures for real-life device applications, were found to be mechanically robust (Young's modulus in excess of 29 GPa) and exhibited high native electrical conductivity (2508 ± 632 S m(-1)) and exceptionally high specific surface area (2605 m(2) g(-1) before reduction and 2210 m(2) g(-1) after reduction). Furthermore, the highly porous nature of these architectures enabled us to translate the superior electrochemical properties of individual graphene sheets into practical everyday use devices with complex geometrical architectures. The as-prepared final architectures exhibited an open network structure with a continuous ion transport network, resulting in unrivaled charge storage capacity (409 F g(-1) at 1 A g(-1)) and rate capability (56 F g(-1) at 100 A g(-1)) while maintaining their strong flexible nature.

Graphene oxide nanopaint

Nanostructured materials are receiving growing interest in the development of a number of commercial products. In this study, we have developed a multifunctional graphene oxide (GO) nanopaint by incorporating GO sheets in an alkyd resin with suitable non-toxic additives using ball milling. The drying mechanism of the GO nanopaint has been discussed. Intermolecular cross-linking between GO and the lipid chains in the alkyd resin was studied by Fourier transform infra red spectra, Raman spectra, and X-ray photoelectron spectra, respectively. The prepared GO nanopaint exhibited good corrosion-resistant behavior in both acidic and high-salt-content solutions as examined by the immersion and electrochemical corrosion tests. The GO nanopaint coating possesses a corrosion protection efficiency of about 76% in salt water as estimated from the linear polarization studies. The antibacterial property of the GO nanopaint coated surface was studied against three bacterial strains (Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa) and the results showed that GO nanopaint inhibited the bacterial growth on its surface. The in situ biofouling tests demonstrated the inhibition of fouling on the GO nanopaint surface.

Multifunctional hybrid graphene oxide for label-free detection of malignant melanoma from infected blood.

This communication reports for the first time the development of multifunctional graphene oxide for the ultra-sensitive and label-free detection of malignant melanoma from an infected blood sample.

Synthesis of graphene–polyurethane nanocomposite using highly functionalized graphene oxide as pseudo-crosslinker

Synthesis and characterization of graphene–polyurethane nanocomposites has been carried out using highly functionalized graphene oxide. Multi-functional graphene oxide has been prepared and used as a pseudo-crosslinker in the preparation of graphene–polyurethane nanocomposites to enhance the three-dimensional grafting of polyurethane chains onto graphene surfaces. The enhanced hydroxyl-group-functionalized graphene oxide was used as a pseudo-crosslinker with NCO-terminated prepolymer to form graphene–polyurethane nanocomposites without any other chain extenders. The resulting nanocomposites showed enhanced thermal stability when compared with virgin polyurethanes.

Multifunctional graphene oxide–TiO2 microsphere hierarchical membrane for clean water production

The severe scarcity of clean water is arousing concern worldwide. The development of clean water production heavily relies on membrane technology, although the performance of current membranes is significantly restricted by membrane fouling. In this work, a novel graphene oxide (GO)–TiO2 microsphere hierarchical membrane was fabricated through assembling GO–TiO2 microsphere composite on the surface of a polymer filtration membrane. This kind of membrane possesses the multifunction of concurrent water filtration and degradation of pollutants. GO sheets play double roles in GO–TiO2 membrane, including (1) cross linker for individual TiO2 microspheres; and (2) electron acceptor to enhance photocatalytic activity. Hence, this novel membrane shows sustainably high permeate flux due to the hierarchical membrane structure, high photodegradation activity and no membrane fouling. The excellent performance of this GO–TiO2 hierarchical membrane indicates its promising potential in clean water production field.

Multi-functionalized graphene oxide based anticancer drug-carrier with dual-targeting function and pH-sensitivity

A dual-targeting drug delivery and pH-sensitive controlled release system based on multi-functionalized graphene oxide (GO) was established in order to enhance the effect of targeted drug delivery and realize intelligently controlled release. A superparamagnetic GO–Fe3O4 nanohybrid was firstly prepared via a simple and effective chemical precipitation method. Then folic acid, a targeting agent toward some tumor cells, was conjugated onto Fe3O4 nanoparticlesvia the chemical linkage with amino groups of the 3-aminopropyl triethoxysilane (APS) modified superparamagnetic GO–Fe3O4 nanohybrid, to give the multi-functionalized GO. Doxorubicin hydrochloride (Dox) as an anti-tumor drug model was loaded onto the surface of this multi-functionalized GO via π–π stacking. The drug loading capacity of this multi-functionalized GO is as high as 0.387 mg mg−1 and the drug release depends strongly on pH values. Cell uptake studies were carried out using fluorescein isothiocyanate labeled or Dox loaded multi-functionalized GO to evaluate their targeted delivery property and toxicity to tumor cells. The results show that this multi-functionalized GO has potential applications for targeted delivery and the controlled release of anticancer drugs.