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Graphen Oxide

M Checa, M Figueredo, A Aguinaco, F J Beltrán
A graphene oxide-titania (GO/TiO2 ) composite was synthesized via sol-gel method, and studied in aqueous Primidone mineralization with ozone and LED visible light. The photocatalyst was characterized by different techniques (XRD, TEM, SBET, TGA, UV-vis diffuse reflectance spectroscopy). The band gap value decrease from 3.14 eV for bare TiO2 samples to 2.5 eV in GO/TiO2 composites clearly shows the interaction of GO with TiO2 structure. Approximately 20 mg L-1 of Primidone was removed in less than 20 min if ozone was applied, regardless of the presence or absence of light and catalyst...
February 10, 2019: Journal of Hazardous Materials
Han-Bin Meng, Xiao-Fang Zhang, Yu-Lu Pu, Xue-Lu Chen, Jiu-Ju Feng, De-Man Han, Ai-Jun Wang
Pt-based nanocomposites with low Pt utilization and high-activity by incorporating with other transition metals have received significant interest in catalysis. Meanwhile, loading Pt-based catalysts on graphene has great research value for improved stability and dispersity of the catalysts. Herein, a facile l-proline-mediated solvothermal strategy was reported to construct reduced graphene oxide (rGO) supported sheet-like PtCo nanocrystals (Pt78 Co22 NCs/rGO) in ethylene glycol (EG). The as-synthesized nanocomposite manifested remarkably improved catalytic properties and chemical stability for oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER), surpassing home-made Pt29 Co71 nanoparticles (NPs)/rGO, Pt83 Co17 NPs/rGO, Pt52 Co48 NPs, commercial Pt/C and Pt black catalysts...
January 28, 2019: Journal of Colloid and Interface Science
Ehsan Saburi, Maryam Islami, Simzar Hosseinzadeh, Abbas Shapouri Moghadam, Reyhaneh Nassiri Mansour, Esmaeel Azadian, Zeinab Joneidi, Amin Reza Nikpoor, Mohammad Hassan Ghadiani, Zohreh Khodaii, Abdolreza Ardeshirylajimi
Due to the several limitations that surgeons are faced during bone tissue implantation there are daily increases in introducing new cell-co-polymer composites for use in bone tissue engineering approaches. In this study tried to develop a suitable nanostructured bio-composite for enhancing osteogenic differentiation of the human induced pluripotent stem cells (iPSCs). Polyvinylidene fluoride-Graphene oxide (PVDF-GO) nanofibers was fabricated by electrospinning and then characterized using scanning electron microscope, tensile and viability assays...
February 14, 2019: Gene
Peng He, Jiushun Zhou, Huixia Tang, Siwei Yang, Zhi Liu, Xiaoming Xie, Guqiao Ding
Large-sized graphene oxide (LGO) is desirable for many graphene-based applications. Herein, for the first time, we synthesized LGO (83 µm average size) using electrochemically modified graphite as the precursor. With this strategy, we could reduce both the oxidation time (1 h) and oxidant dosage (2 equiv.) while achieving a fast and high-yield (∼90.3 wt%) LGO preparation. LGO papers show much better mechanical properties and nearly four times higher conductivity (after reduction) than their counterparts assembled using small-sized GO...
February 8, 2019: Journal of Colloid and Interface Science
Liangyun Yu, Qi Zhang, Dangqin Jin, Qin Xu, Xiaoya Hu
A novel NH4 + voltammetric electrochemical biosensor was constructed by immobilizing glutamate dehydrogenase (GLDH)/Fe3 O4 /graphene (GR)/chitosan (CS) nanobiocomposite onto a glassy carbon electrode (GCE). On the GLDH/Fe3 O4 /GR/CS/GCE, GLDH catalyzed the reversible reaction, i.e., the reductive amination of α-ketoglutaric acid and the oxidative deamination of L-glutamate. The electrons produced in the enzymatic reactions were transferred to the surface of the electrode via the [Fe(CN)6 ]3-/4- couple, which helped for the amplification of the electrochemical signal...
May 15, 2019: Talanta
Fatemeh Ahmadi Tabr, Farah Salehiravesh, Hossein Adelnia, Jaber Nasrollah Gavgani, Mojtaba Mahyari
In this paper, we presented the fabrication and properties of new ammonia (NH3 ) sensors with sensitive layer of nickel nanoparticles decorated on three-dimensional nitrogen-doped graphene-based frameworks/polyaniline (NiNPs@3D-(N)GFs/PANI) hybrid. The hybrid are synthesized through in-situ oxidative polymerization on flexible thin substrate. Synergetic behavior between both components manifested outstanding sensitivity (750.2 at 1000 ppm NH3 ) and quick response (95 s) and recovery (25 s) times and a lower limit of detection (~ 45 ppb) at room temperature...
May 15, 2019: Talanta
Ming-Hua Jing, Xi-Ming Song, Da-Wei Fang, Ling Zhang, Qian Zhang
In this article, a novel electroactivity-adjustable poly (ionic liquids)/reduced graphene oxide (PIL-GP) was developed and utilized for the fabrication of multifunctional, high stable electrochemical sensors. The structure, morphology and surface charge properties of PIL-GP have been systematically studied. And the selective detection performance of dopamine (DA) on PIL-GP modified glassy carbon electrode (GCE) were further explored by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). More importantly, by virtue of the anion exchange property of PIL, electroactive Fe(CN)6 3- /PIL-GP/GCE and Polyoxometalates (PWA)/PIL-GP/GCE were easily fabricated and their electrochemical detection performance of ascorbic acid (AA) and bromate were investigated respectively...
May 15, 2019: Talanta
Shuang Tan, Rui Han, Shilian Wu, Huan Liang, Yuting Zhao, Hui Zhao, Can-Peng Li
Competitive host-guest recognition has been utilized to determine small molecules using macrocyclic supramolecular host, while less studies focused on the specific recognition and sensing of protein. In the present work, we are the first time to report a label-free fluorescent assay for insulin determination based on the supramolecular recognition between cationic pillar[6]arene (CP6) and insulin. The approach is based on fluorescence resonance energy transfer (FRET) through competitive recognition between CP6 functionalized reduced graphene oxide (CP6@rGO) and probe/insulin molecules...
May 15, 2019: Talanta
S Taniselass, M K Md Arshad, Subash C B Gopinath
Graphene is a 2-dimensional nanomaterial with an atomic thickness has attracted a strong scientific interest owing to their remarkable optical, electronic, thermal, mechanical and electrochemical properties. Graphene-based materials particularly graphene oxide and reduced graphene oxide are widely utilized in various applications ranging from food industry, environmental monitoring and biomedical fields as well as in the development of various types of biosensing devices. The richness in oxygen functional groups in the materials serves as a catalysis for the development of biosensors/electrochemical biosensors which promotes for an attachment of biological recognition elements, surface functionalization and compatible with micro- and nano- bio-environment...
January 29, 2019: Biosensors & Bioelectronics
Minling Gao, Yujuan Yang, Zhengguo Song
Graphene oxide (GO) is extensively used in various fields because of its versatility. The presence of GO in the environment enhances the toxicity of toxicants or pollutants. Cadmium (Cd) and GO pollution is a problem in aquatic environment, which should be solved. We investigated the toxic effects of Cd on photosynthesis and oxidative stress in wheat seedlings in the presence of GO, by measuring seedling biomass, Cd content, photosynthesis, reactive oxygen species (ROS) level, antioxidant enzyme activities, and malondialdehyde (MDA) content...
February 13, 2019: Ecotoxicology and Environmental Safety
Ebrahim Mahmoudi, Wei Lun Ang, Ching Yin Ng, Law Yong Ng, Abdul Wahab Mohammad, Abdelbaki Benamor
Graphene oxide (GO) has gained popularity in scientific research and industry due to its superior properties, which can be controlled by the synthesis method and graphite feedstock. Despite the availability of different graphite sources, most of the reported studies used natural graphite flake (NGF) as a source of oxidation for GO synthesis. The effect of various alternative graphite feedstocks on the GO properties has not been investigated systematically. This study investigated the influence of graphite feedstock (natural and synthetic) on the characteristics and properties of GO via modified Hummer's method...
February 7, 2019: Journal of Colloid and Interface Science
Junyi Wang, Yucheng Li, Zhimin Lv, Yi Xie, Junjie Shu, Ahmed Alsaedi, Tasawar Hayat, Changlun Chen
A novel composite of zeolitic imidazolate framework grown on graphene oxide (ZIF-8@GO) was successfully prepared and used for the adsorption of Pb(II) and 1-naphthylamine from aqueous solutions. The effects of contact time, pH, ionic strength and temperature on the adsorption performance of ZIF-8@GO was investigated by batch experiments. Compared to the bare ZIF-8 and GO, the ZIF-8@GO exhibited a significant increase in the adsorption for Pb(II) and 1-naphthylamine. The maximum adsorption capacities of ZIF-8@GO towards Pb(II) and 1-naphthylamine reached 356...
February 11, 2019: Journal of Colloid and Interface Science
Gayong Shim, Quoc-Viet Le, Juhan Suh, Sunhee Choi, Gunwoo Kim, Han-Gon Choi, Young Bong Kim, M B Macgregor, Yu-Kyoung Oh
The combination of imaging and anticancer therapy has recently emerged as a promising strategy. However, nonspecific imaging signals and distribution of anticancer drugs at normal tissues limit the specificity of the combination therapy. To overcome the challenges, we designed a system which can selectively visualize cancer tissues and initiate the subsequent action of therapeutic molecules in tumor microenvironment. Exploiting the overexpression of matrix metalloproteinase (MMP) in the tumor microenvironment, we designed a graphene oxide (GO)-based nanosheet system loaded with a pegylated MMP-cleavable imaging probe and an anticancer peptide shielded under the imaging probe...
February 13, 2019: Journal of Controlled Release: Official Journal of the Controlled Release Society
Anu Bharti, Navneet Agnihotri, Nirmal Prabhakar
An electrochemical hybridization assay is described for the determination of microRNA-21. Fluorine tin oxide (FTO) sheets were coated with carboxylated graphene oxide followed by deposition of gold-platinum bimetallic nanoparticles by using chronoamperometry at a potential of -0.2 V for 350 s. The capture probe was immobilized on the surface of the modified FTO sheets by biotin-avidin interaction. On exposure to microRNA-21, hybridization occurs, and that can be detected at a relatively low working potential of 0...
February 15, 2019: Mikrochimica Acta
Hua Ye, Nuo Duan, Huajie Gu, Haitao Wang, Zhouping Wang
A broad-spectrum ssDNA aptamer containing 80 nucleotides (LA80) and capable of binding to four different sources of lipopolysaccharides (LPSs) was truncated. Two strategies are used to produce truncated aptamers of different length. The results show that LA27, a 27-nt aptamer, retained broad-spectrum capability and has a higher affinity (Kd  = 46.2 ± 9.5 nM). A graphene oxide based fluorescence polarization assay (excitation/emission wavelengths: 485/520 nm) was worked out using FAM-labeled LA27...
February 15, 2019: Mikrochimica Acta
Huazhen Duan, Wei Deng, Zhenfei Gan, Dan Li, Dawei Li
A method is described for surface-enhanced Raman scattering (SERS) discrimination of formaldehyde (FA) and acetaldehyde (AA) in aqueous sample solutions. It is based on the use of a paper strip containing 4-aminothiophenol (Atp)-modified reduced graphene oxide (rGO)/[Ag(NH3 )2 ]+ (rGO/[Ag(NH3 )2 ]+ /Atp). The addition of FA or AA induces the conversion of [Ag(NH3 )2 ]+ complex to silver nanoparticles (AgNPs) because of aldehyde-induced silver reduction reaction. The AgNPs possess strong SERS activity. The average interparticle gaps between the AgNPs can be fine-tuned by controlling the experimental conditions, this leading to the formation of optimized SERS hot spots...
February 15, 2019: Mikrochimica Acta
Fen-Ying Kong, Rong-Fang Li, Lei Yao, Zhong-Xia Wang, Heng-Ye Li, Wei-Xin Lv, Wei Wang
An electrochemical sensor is described for the simultaneous determination of the pollutants catechol (CC) and hydroquinone (HQ). A glassy carbon electrode (GCE) was modified with reduced graphene oxide, Fe3 O4 and gold nanoparticles and then showed a pair of well-defined voltammetric peaks for CC and HQ. Its oxidation peak potentials (located at 0.21 and 0.10 V vs. Ag/AgCl) are well separated, and this makes it suitable for simultaneous determination of the two isomers. Under optimal conditions, the oxidation peak currents of CC and HQ increase linearly in the 0...
February 15, 2019: Mikrochimica Acta
Qian Zhang, Dong-Dong Zhou, Fan Li, Yin-Zhen Wang, Feng-Qing Yang
A magnetite@graphene oxide nanocomposite was first coated with polyethylenimine and then modified with phytic acid and titanium(IV) ions. The high loading with Ti(IV) and the good hydrophilicity of PEI and PA result in a material that can be applied to the efficient extraction of highly polar nucleobases, nucleosides and nucleotides. The physicochemical properties of the composite were investigated by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, water contact angle measurements, thermogravimetric analysis, and vibrating sample magnetometry...
February 15, 2019: Mikrochimica Acta
Haiping Huang, Yafeng Yue, Zhongzhen Chen, Yanan Chen, Shuzhen Wu, Jinsheng Liao, Suijun Liu, He-Rui Wen
A nanocomposite is described that consists of TmPO4 and graphene oxide (GO) and is used to modify a glassy carbon electrode (GCE) to obtain a sensor for simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). GO and TmPO4 were synthesized via the Hummers method and by a hydrothermal method, respectively. The nanocomposite was characterized by transmission electron microscopy, energy dispersive X-ray spectroscopy, powder X-ray diffraction and Fourier transform infrared spectroscopy...
February 15, 2019: Mikrochimica Acta
Kornelia Lewandowska, Natalia Rosiak, Andrzej Bogucki, Judyta Cielecka-Piontek, Mikołaj Mizera, Waldemar Bednarski, Maciej Suchecki, Konrad Szaciłowski
Graphene oxide (GO) was modified by two modified porphyrins (THPP and TCPP) to form GO⁻porphyrin hybrids. Spectroscopic measurements demonstrated the formation of stable supramolecular aggregates when mixing two components in solution. The Fourier transform infrared (FTIR) and Raman scattering measurements confirm π-stacking between hydrophobic regions of GO nanoflakes and porphyrin molecules. On the number and the kind of paramagnetic centers generated in pristine GO samples, which originate from spin anomalies at the edges of aromatic domains within GO nanoflakes...
February 14, 2019: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
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