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Lingjuan Deng, Yihong Gao, Zhanying Ma, Guang Fan
Preparation of free-standing electrode materials with three-dimensional network architecture has emerged as an effective strategy for acquiring advanced portable and wearable power sources. Herein, graphene/vanadium oxide (GR/V2O5) free-standing monolith composite has been prepared via a simple hydrothermal process. Flexible GR sheets acted as binder to connect the belt-like V2O5 for assembling three-dimensional network architecture. The obtained GR/V2O5 composite can be reshaped into GR/V2O5 flexible film which exhibits more compact structure by ultrasonication and vacuum filtration...
June 16, 2017: Journal of Colloid and Interface Science
Qian Zhou, Youxiu Lin, Jian Shu, Kangyao Zhang, Zhenzhong Yu, Dianping Tang
A new and signal-on photoelectrochemical (PEC) sensing platform was successfully designed for the sensitive detection of prostate-specific antigen (PSA), using reduced graphene oxide- functionalized iron oxyhydroxide (FeOOH-rGO) as the photoactive material, accompanying target-responsive controlled release system to achieve the signal amplification. Introduction of rGO as electron mediator greatly facilitated the electron transfer from FeOOH to electrode under visible light, which inhibited the electron-hole recombination to enhance the photo-activity of FeOOH-rGO...
June 16, 2017: Biosensors & Bioelectronics
Meiqing Chen, Pingxiao Wu, Liya Chen, Shanshan Yang, Langfeng Yu, Yuefei Ding, Nengwu Zhu, Zhenqing Shi, Zehua Liu
Three-dimensional multi-doped porous carbon/graphene (Fe-Mt-SS-C) was prepared by carbonization of sewage sludge with template-assisted Fe-pillared montmorillonite. The material consisted of nanosheet- and particle- carbon had a high specific surface area (784.46 m(2)·g(-1)) and hierarchical porous structure of micro-, meso- and macropores. The prepared Fe-Mt-SS-C had a high degree of graphitization and large amount of defect atoms. The pyrolysis process made full use of the C, N, Fe, and S by turning them into the carbon framework of the as-obtained material in situ...
June 23, 2017: Scientific Reports
Priya T, Dhanalakshmi N, Thinakaran N
In this study, we developed a novel composite material containing biological macromolecules like heparin and chitosan coated on reduced graphene oxide (rGO) for the modification of glassy carbon electrode (hep/CS-rGO/GC). It can be applied for the sensitive electrochemical detection of Pb(2+) by square wave anodic stripping voltammetry (SWASV). The physicochemical analysis such as XRD, FTIR, FESEM and Raman spectroscopy techniques revealed that an effective functionalization occurred at the rGO surface. The consequence of deposition and stripping of metal ions by various electrochemical parameters such as supporting electrolytes, pH value, deposition potential, and deposition time were carefully studied and optimized...
June 20, 2017: International Journal of Biological Macromolecules
Chun-Jiao Lu, Xue-Feng Jiang, Muhammad Junaid, Yan-Bo Ma, Pan-Pan Jia, Hua-Bin Wang, De-Sheng Pei
Graphene oxide (GO) has widespread concerns in the fields of biological sciences and medical applications. Currently, studies have reported that excessive GO exposure can cause cellular DNA damage through reactive oxygen species (ROS) generation. However, DNA damage mediated response of the base excision repair (BER) pathway due to GO exposure is not elucidated yet. Therefore, we exposed HEK293T cells and zebrafish embryos to different concentrations of GO for 24 h, and transcriptional profiles of BER pathway genes, DNA damage, and cell viability were analyzed both in vitro and in vivo...
June 14, 2017: Chemosphere
Vasilii I Popov, Danil Nikolaev, Vladimir B Timofeev, Svetlana Smagulova, Irina Antonova
The response of graphene based humidity sensor is considered as a function of film structures. Analysis of resistance changes due to water molecule adsorption on graphene or multigraphene (MLG) surface is performed for films with a different resistivity from hundreds of Ohm/sq to hundreds of kOhm/sq. It has revealed a possible increase, decrease and non monotonous behavior of resistance. Adsorption of water molecules at grain boundary defects is supposed to lead to an increase in film resistivity due to the donor property of water and p-type conductivity of graphene...
June 23, 2017: Nanotechnology
Jose Maria Munuera, Juan Ignacio Paredes, Marina Enterria, Ana Pagán, Silvia Villar-Rodil, Manuel Fernando R Pereira, J I Martins, José L Figueiredo, Jose Luis Cenis, Amelia Martinez-Alonso, Juan Manuel D Tascon
Graphene and graphene-based materials have shown great promise in many technological applications, but their large-scale production and processing by simple and cost-effective means still constitute significant issues in the path of their widespread implementation. Here, we investigate a straightforward method for the preparation of a ready-to-use and low oxygen content graphene material that is based on electrochemical (anodic) delamination of graphite in aqueous medium with sodium halides as the electrolyte...
June 23, 2017: ACS Applied Materials & Interfaces
R X Chu, J Lin, C Q Wu, J Zheng, Y L Chen, J Zhang, R H Han, Y Zhang, H Guo
Lithium-sulfur (Li-S) batteries have attracted great attention owing to their excellent electrochemical properties, such as the high discharge voltage of 2.3 V, specific capacity of 1675 mA h g(-1) and energy density of 2600 Wh kg(-1). The widely used slurry made electrodes of Li-S batteries are plagued by the serious shuttle effect and insulating nature of sulfur. Herein, a reduced graphene oxide coated porous carbon nanofiber flexible paper (rGO@S-PCNP) was fabricated and directly used as an additive-free cathode for Li-S batteries...
June 23, 2017: Nanoscale
Minglei Sun, Jyh-Pin Chou, Jin Yu, Wencheng Tang
Blue phosphorene (BlueP) is a graphene-like phosphorus nanosheet which was synthesized very recently for the first time [Nano Lett., 2016, 16, 4903-4908]. The combination of electronic properties of two different two-dimensional materials in an ultrathin van der Waals (vdW) vertical heterostructure has been proved to be an effective approach to the design of novel electronic and optoelectronic devices. Therefore, we used density functional theory to investigate the structural and electronic properties of two BlueP-based heterostructures - BlueP/graphene (BlueP/G) and BlueP/graphene-like gallium nitride (BlueP/g-GaN)...
June 23, 2017: Physical Chemistry Chemical Physics: PCCP
Yaping He, Xiaohui Yang, Quan Han, Jianbin Zheng
A novel catechol (CA) biosensor was developed by embedding tyrosinase (Tyr) onto in situ electrochemical reduction graphene (EGR) on choline-functionalized gold nanoparticle (AuNPs-Ch) film. The results of UV-Vis spectra indicated that Tyr retained its original structure in the film, and an electrochemical investigation of the biosensor showed a pair of well-defined, quasi-reversible redox peaks with Epa = -0.0744 V and Epc = -0.114 V (vs. SCE) in 0.1 M, pH 7.0 sodium phosphate-buffered saline at a scan rate of 100 mV/s...
June 23, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Xiaoqin Wang, Guizhen Li, Kyung Ho Row
Magnetic graphene oxide was modified by four imidazole-based ionic liquids to synthesize materials for the extraction of polysaccharides by magnetic solid-phase extraction. Fucoidan and laminarin were chosen as the representative polysaccharides owing to their excellent pharmaceutical value and availability. FTIR spectroscopy, field-emission scanning electron microscopy and thermogravimetric analysis were applied to characterize the synthesized materials. Single-factor experiments showed that the extraction efficiency of polysaccharides was affected by the amount of ionic liquids for modification, solid-liquid ratio of brown alga and ethanol, the stirring time of brown alga and ionic liquid modified magnetic graphene oxide materials, and amount of 1-(3-aminopropyl)imidazole chloride modified magnetic graphene oxide materials added to the brown alga sample solution...
June 23, 2017: Journal of Separation Science
Vezio Bianchi, Tian Carey, Leonardo Viti, Lianhe Li, Edmund H Linfield, A Giles Davies, Alessandro Tredicucci, Duhee Yoon, Panagiotis G Karagiannidis, Lucia Lombardi, Flavia Tomarchio, Andrea C Ferrari, Felice Torrisi, Miriam S Vitiello
Saturable absorbers (SA) operating at terahertz (THz) frequencies can open new frontiers in the development of passively mode-locked THz micro-sources. Here we report the fabrication of THz SAs by transfer coating and inkjet printing single and few-layer graphene films prepared by liquid phase exfoliation of graphite. Open-aperture z-scan measurements with a 3.5 THz quantum cascade laser show a transparency modulation ∼80%, almost one order of magnitude larger than that reported to date at THz frequencies...
June 15, 2017: Nature Communications
Yunjie Li, Xiaoxiao Hu, Ding Ding, Yuxiu Zou, Yiting Xu, Xuewei Wang, Yin Zhang, Long Chen, Zhuo Chen, Weihong Tan
Helicobacter pylori infection is implicated in the aetiology of many diseases. Despite numerous studies, a painless, fast and direct method for the in situ detection of H. pylori remains a challenge, mainly due to the strong acidic/enzymatic environment of the gastric mucosa. Herein, we report the use of stable magnetic graphitic nanocapsules (MGNs), for in situ targeted magnetic resonance imaging (MRI) detection of H. pylori. Several layers of graphene as the shell effectively protect the magnetic core from corrosion while retaining the superior contrast effect for MRI in the gastric environment...
June 15, 2017: Nature Communications
Shuhua Li, Shixin Zhou, Yunchao Li, Xiaohong Li, Jia Zhu, Louzhen Fan, Shihe Yang
IR780 iodide (IR780) is recognized as an effective theranostic agent for simultaneous near-infrared (NIR) fluorescence imaging and photothermal therapy (PTT). However, the rigid chloro-cyclohexenyl ring makes IR780 insoluble in almost all pharmaceutically acceptable solvents, which inevitably limits its clinical application. We report folic acid (FA)-functionalized graphene quantum dots (GQDs-FA) containing a large and intact sp2-domain with carboxyl groups around the edge. Such GQDs-FA possess exceptionally high loading capacity for IR780 via strong π-π stacking interactions, and the water solubility of IR780 is improved by over 2400-fold after loading onto GQDs-FA (IR780/GQDs-FA)...
June 23, 2017: ACS Applied Materials & Interfaces
Wen Li, Daryl McManus, Han Liu, Cinzia Casiraghi, Simon J Webb
The addition of amines to an aldehyde surfactant, which was designed to be analogous to didodecyldimethylammonium bromide, gave exchangeable "iminolipids" that self-assembled to give stable aqueous dispersions of nano-sized vesicles. For example, sonication of suspensions of the n-hexylamine-derived iminolipid gave vesicles 50 to 200 nm in diameter that could encapsulate a water-soluble dye. The iminolipids could undergo dynamic exchange with added amines, and the resulting equilibrium constants (Krel) were quantified by (1)H NMR spectroscopy...
June 23, 2017: Physical Chemistry Chemical Physics: PCCP
Anja Aarva, Tomi Laurila, Miguel A Caro
In this work, we study the adsorption characteristics of dopamine (DA), ascorbic acid (AA), and dopaminequinone (DAox) on carbonaceous electrodes. Our goal is to obtain a better understanding of the adsorption behavior of these analytes in order to promote the development of new carbon-based electrode materials for sensitive and selective detection of dopamine in vivo. Here we employ density functional theory-based simulations to reach a level of detail that cannot be achieved experimentally. To get a broader understanding of carbonaceous surfaces with different morphological characteristics, we compare three materials: graphene, diamond, and amorphous carbon (a-C)...
June 21, 2017: Journal of Chemical Physics
Wei Tao, Xiaoyuan Ji, Xiaoding Xu, Mohammad Ariful Islam, Zhongjun Li, Si Chen, Phei Er Saw, Han Zhang, Zameer Bharwani, Zilei Guo, Jinjun Shi, Omid Farokhzad
Photothermal therapy (PTT) has shown significant potential for cancer therapy. However, developing nanomaterials (NMs)-based photothermal agents (PTAs) with satisfactory photothermal conversion efficacy (PTCE) and biocompatibility remains a key challenge. Herein, a new generation of PTAs based on two-dimensional (2D) antimonene quantum dots (AMQDs) was developed by a novel liquid exfoliation method. Surface modification of AMQDs with polyethylene glycol (PEG) significantly enhanced both biocompatibility and stability in physiological medium...
June 22, 2017: Angewandte Chemie
Mohammad Sabzi, Masoud Babaahmadi, Mohammadreza Rahnama
This work aimed to develop a facile and broadly applicable method for fabricating a multi-stimuli responsive triple-shape memory polymer (SMP). Hence, herein the SMPs were prepared through the simple physical blending of two commercially available biopolymers, poly(lactic acid) (PLA) and poly(vinyl acetate) (PVAc), in the presence of robust and conductive graphene nanoplatelets. Interestingly, atomic force microscopy (AFM) observations and thermal analyses revealed that the presence of nanofillers led to phase separation and appearance of two well-separated transition temperatures in the blend of these two miscible polymers...
June 22, 2017: ACS Applied Materials & Interfaces
Zicheng Wang, Renbo Wei, Xiaobo Liu
Highly ordered nitrogen-doped graphene multilayer films with large interlayer void are successfully fabricated by thermal annealing the compact stacking graphene oxide/copper phthalocyanine (GO/CuPc) multilayer films. Scanning electron microscopic (SEM), X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopic (XPS) and electrical conductivity measurements indicate that the breakaway of oxygen functional groups on/in the GO sheets at high temperature and the in-situ pyrolysis of CuPc molecules in the interlayer of graphene sheets synergistically facilitate the restoration of GO in graphitization, the effective nitrogen doping by replacing carbon atoms in graphene frameworks, the retention of layer-by-layer stacking structure of graphene sheets in plane and the formation of interlayer voids, leading to the enhancement in the electrical conductivity (3...
June 22, 2017: ACS Applied Materials & Interfaces
Bo Chen, Haifeng Jiang, Xiang Liu, Xuejiao Hu
Transport of ionic solutions through graphene oxide (GO) membranes is a complicated issue because the complex and tortuous structure inside make it very hard to clarify. Using molecular dynamics (MD) simulations, we investigated the mechanism of water transport and ions movement across the multilayer graphene oxide. The significant flow rate is considerably influenced by the structural parameters of GO membranes. Due to the size effect on shrunken real flow area, there is disagreement between classical continuum model and nano-scaled flow...
June 22, 2017: ACS Applied Materials & Interfaces
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