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graphene oxide

Raj Kumar Thapa, Jae Hee Kim, Jee-Heon Jeong, Beom Soo Shin, Han-Gon Choi, Chul Soon Yong, Jong Oh Kim
Combination therapies are widely investigated cancer treatment modalities. Carbon based systems such as graphene oxide (GO), plasmonic nanoparticles such as silver nanoparticles (AgNPs), and the folate analog, methotrexate (MTX), have been separately studied for their potential anticancer effects. In this study, we combined these systems to develop AgNPs-embedded GO with conjugated MTX (MTX-GO/AgNPs) and studied their folate receptor-targeted anticancer effects. Results revealed successful formation of AgNPs on GO along with MTX conjugation as suggested by UV/visible, TEM, AFM, FTIR, and XRD analysis...
February 13, 2017: Colloids and Surfaces. B, Biointerfaces
Somnath Chakraborty, A N Resmi, Renuka Pothuraju, K B Jinesh
Chemically reduced graphene oxide (rGO) samples with various degree of reduction were prepared using hydrazine hydrate as the reducing agent. Scanning tunnelling microscope (STM) imaging shows that rGO contains rows of randomly distributed patches of epoxy groups. The local density of states (LDOS) of the rGO samples were mapped with scanning tunnelling spectroscopy (STS), which shows that the bandgap in rGO originates from the epoxide regions itself. The Fermi level of the epoxide regions is shifted towards the valence band, making rGO locally p-type and a ranges of bandgaps from 0-2...
February 23, 2017: Nanotechnology
Jill Z Manapat, Joey Dacula Mangadlao, Brylee David Buada Tiu, Grace C Tritchler, Rigoberto C Advincula
The weak thermomechanical properties of commercial 3D printing plastics have limited the technology's application mainly to rapid prototyping. In this report, we demonstrate a simple approach that takes advantage of the metastable, temperature-dependent structure of graphene oxide (GO) to enhance the mechanical properties of conventional 3D-printed resins produced by stereolithography (SLA). A commercially available SLA resin was reinforced with minimal amounts of GO nanofillers and thermally annealed at 50 °C and 100 °C for 12 hours...
February 23, 2017: ACS Applied Materials & Interfaces
Masumeh Foroutan, S Mahmood Fatemi, Farshad Esmaeilian
During the past decade, the research on fluids in nanoconfined geometries has received considerable attention as a consequence of their wide applications in different fields. Several nanoconfined systems such as water and ionic liquids, together with an equally impressive array of nanoconfining media such as carbon nanotube, graphene and graphene oxide have received increasingly growing interest in the past years. Water is the first system that has been reviewed in this article, due to its important role in transport phenomena in environmental sciences...
February 2017: European Physical Journal. E, Soft Matter
B Melai, P Salvo, N Calisi, L Moni, A Bonini, C Paoletti, T Lomonaco, V Mollica, R Fuoco, F Di Francesco, B Melai, P Salvo, N Calisi, L Moni, A Bonini, C Paoletti, T Lomonaco, V Mollica, R Fuoco, F Di Francesco, F Di Francesco, L Moni, P Salvo, T Lomonaco, R Fuoco, V Mollica, C Paoletti, A Bonini, N Calisi, B Melai
This article describes the fabrication and characterization of a pH sensor for monitoring the wound status. The pH sensitive layer consists of a graphene oxide (GO) layer obtained by drop-casting 5 μΐ of GO dispersion onto the working electrode of a screen-printed substrate. Sensitivity was 31.8 mV/pH with an accuracy of 0.3 unit of pH. Open-circuit potentiometry was carried out to measure pH in an exudate sample. The GO pH sensor proved to be reliable as the comparison with results obtained from a standard glass electrode pH-meter showed negligible differences (<; 0...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Rajesh Kumar, Rajesh Kumar Singh, Alfredo R Vaz, Raluca Savu, Stanislav A Moshkalev
In the present work, we have synthesized three dimensional (3D) reduced graphene oxide nanosheets (rGO NSs) containing iron oxide nanoparticles (Fe3O4 NPs) hybrids (3D Fe3O4/rGO) by one-pot microwave approach. Structural and morphological studies reveal that the as-synthesized Fe3O4/rGO hybrids were composed of faceted Fe3O4 NPs induced into the interconnected network of rGO NSs. The morphologies and structures of the 3D hybrids have been characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectrometer (XPS)...
February 22, 2017: ACS Applied Materials & Interfaces
Grant J Stec, Adam Lauchner, Yao Cui, Peter Nordlander, Naomi J Halas
Polycyclic aromatic hydrocarbon (PAH) molecules, the hydrogen-terminated, subnanometer scale version of graphene, support plasmon resonances with the addition or removal of a single electron. Typically colorless when neutral, they are transformed into vivid optical absorbers in either their positively or negatively charged states. Here we demonstrate a low-voltage, multistate electrochromic device based on PAH plasmon resonances that can be reversibly switched between nearly colorless (0 V), olive (+4 V), and royal blue (-3...
February 22, 2017: ACS Nano
R Vinoth, S Ganesh Babu, Vishal Bharti, V Gupta, M Navaneethan, S Venkataprasad Bhat, C Muthamizhchelvan, Praveen C Ramamurthy, Chhavi Sharma, Dinesh K Aswal, Yasuhiro Hayakawa, B Neppolian
A new class of pyridyl benzimdazole based Ru complex decorated polyaniline assembly (PANI-Ru) was covalently grafted onto reduced graphene oxide sheets (rGO) via covalent functionalization approach. The covalent attachment of PANI-Ru with rGO was confirmed from XPS analysis and Raman spectroscopy. The chemical bonding between PANI-Ru and rGO induced the electron transfer from Ru complex to rGO via backbone of the conjugated PANI chain. The resultant hybrid metallopolymer assembly was successfully demonstrated as an electron donor in bulk heterojunction polymer solar cells (PSCs)...
February 22, 2017: Scientific Reports
Kochaporn Chullasat, Piyaluk Nurerk, Proespichaya Kanatharana, Pamornrat Kueseng, Thanyaporn Sukchuay, Opas Bunkoed
A hybrid monolith sorbent of polypyrrole-coated graphene oxide embedded in polyvinyl alcohol cryogel was prepared and used as an effective solid phase extraction sorbent for the determination of trace sulfonamides. The large surface areas with many adsorption sites of polypyrrole and graphene oxide facilitated the high adsorption of sulfonamides via hydrogen bonding, π-π and hydrophobic interactions. The high porosity of the polyvinyl alcohol cryogel helped to reduce the back pressure that occurs in a conventional packed solid phase extraction cartridge...
April 8, 2017: Analytica Chimica Acta
Nuo Duan, Wenhui Gong, Shijia Wu, Zhouping Wang
An improved SELEX technique was developed for selecting aptamers against ractopamine (RAC) by immobilizing ssDNA library on the magnetic beads. After sixteen selection rounds, a highly enriched ssDNA pool was sequenced and nine families were grouped according to their homology and secondary structures analysis. One representative aptamer candidate from each family was picked out for binding affinity identification by graphene oxide (GO) adsorption platform. The aptamer RAC-6 was demonstrated as the optimal aptamer with high specificity and dissociation constant (Kd) value of 54...
April 8, 2017: Analytica Chimica Acta
Anthony Ruth, Michitoshi Hayashi, Peter Zapol, Jixin Si, Matthew P McDonald, Yurii V Morozov, Masaru Kuno, Boldizsár Jankó
Fluorescence intermittency or blinking is observed in nearly all nanoscale fluorophores. It is characterized by universal power-law distributions in on- and off-times as well as 1/f behaviour in corresponding emission power spectral densities. Blinking, previously seen in confined zero- and one-dimensional systems has recently been documented in two-dimensional reduced graphene oxide. Here we show that unexpected blinking during graphene oxide-to-reduced graphene oxide photoreduction is attributed, in large part, to the redistribution of carbon sp(2) domains...
February 22, 2017: Nature Communications
Hua Liu, Weidan Na, Ziping Liu, Xueqian Chen, Xingguang Su
In this paper, a facile and rapid fluorescence turn-on assay for fluorescent detection of ascorbic acid (AA) was developed by using the orange emission graphene quantum dots (GQDs). In the presence of horse radish peroxidase (HRP) and hydrogen peroxide (H2O2), catechol can be oxidized by hydroxyl radicals and converted to o-benzoquinone, which can significantly quench the fluorescence of GQDs. However, when AA present in the system, it can consume part of H2O2 and hydroxyl radicals to inhibit the generation of o-benzoquinone, resulting in fluorescence recovery...
February 4, 2017: Biosensors & Bioelectronics
V Karthik Nagareddy, Matthew D Barnes, Federico Zipoli, Khue T Lai, Arseny M Alexeev, Monica Felicia Craciun, C David Wright
Graphene oxide (GO) resistive memories offer the promise of low-cost environmentally-sustainable fabrication, high mechanical flexibility and high optical transparency, making them ideally suited to future flexible and transparent electronics applications. However, the dimensional and temporal scalability of GO memories, i.e. how small they can be made and how fast they can be switched, is an area that has received scant attention. Moreover, a plethora of GO resistive switching characteristics and mechanisms has been reported in the literature, sometimes leading to a confusing and conflicting picture...
February 21, 2017: ACS Nano
Jeong-Min Seo, Loon-Seng Tan, Jong-Beom Baek
Popularly utilized oxidation media, via nitric acid/sulfuric acid mixtures, are too corrosive and oxidizing to preserve structural integrity of highly ordered graphitic materials (carbon nanotubes (CNTs) and graphene). Here, for the most commonly used oxidation method, the important advantages of defect/edge-selective functionalization of carbon materials (CNTs/graphene/graphite) in a polyphosphoric acid (PPA)/phosphorous pentoxide (P2 O5 ) medium are elucidated. The optimized PPA/P2 O5 medium is a mild acid that is not only less corrosive than popularly utilized oxidation media, but also has a strong capability to drive Friedel-Crafts acylation by covalently modifying carbon materials...
February 21, 2017: Advanced Materials
Lei Li, Huiting Bi, Shili Gai, Fei He, Peng Gao, Yunlu Dai, Xitian Zhang, Dan Yang, Milin Zhang, Piaoping Yang
A facile strategy has been adopted for the preparation of ZnFe2O4/NRG composite by anchoring ultrasmall ZnFe2O4 nanoparticles on nitrogen-doped reduced graphene (denoted as NRG) for high-performance supercapacitor electrode. Remarkably, the growth of ZnFe2O4 nanocrystals, the reduction of graphitic oxide and the doping of nitrogen to graphene have been simultaneously achieved in one process. It is found that the NRG employed as substrate can not only control the formation of nano-sized ZnFe2O4, but also guarantee the high dispersion without any agglomeration...
February 21, 2017: Scientific Reports
Lei Chen, Dong-Hua Zheng, Ying Zhang, Ya-Ning Wang, Zhang-Run Xu
A three-dimensional reduced graphene oxide aerogel with embedded nickel oxide nanoparticles was prepared by a one-step self-assembly reaction in a short time. The nanoparticles could be captured into the interior of reduced graphene oxide network during the formation of the three-dimensional architecture. The composite exhibited porosity, good biocompatibility and abundant metal affinity binding sites. The aerogel was used to isolate ovalbumin selectively from egg white, and favorable adsorption was achieved at pH 3...
February 21, 2017: Journal of Separation Science
Kook In Han, Seungdu Kim, In Gyu Lee, Jong Pil Kim, Jung-Ha Kim, Suck Won Hong, Byung Jin Cho, Wan Sik Hwang
Cylindrical silk fiber (SF) was coated with Graphene oxide (GO) for capacitive humidity sensor applications. Negatively charged GO in the solution was attracted to the positively charged SF surface via electrostatic force without any help from adhesive intermediates. The magnitude of the positively charged SF surface was controlled through the static electricity charges created on the SF surface. The GO coating ability on the SF improved as the SF's positive charge increased. The GO-coated SFs at various conditions were characterized using an optical microscope, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, and LCR meter...
February 19, 2017: Sensors
Tobias Breuer, Andrea Karthäuser, Hagen W Klemm, Francesca Genuzio, Gina Peschel, Alexander Fuhrich, Thomas Schmidt, Gregor Witte
The novel organic semiconductor dinaphthothienothiophene (DNTT) has gained considerable interest because its large charge carrier mobility and distinct chemical robustness enable the fabrication of organic field effect transistors with remarkable long-term stability under ambient conditions. Structural aspects of DNTT films and their control, however, remain so far largely unexplored. Interestingly, the crystalline structure of DNTT is rather similar to that of the prototypical pentacene, for which the molecular orientation in crystalline thin films can be controlled by means of interface-mediated growth...
February 20, 2017: ACS Applied Materials & Interfaces
Guangxin Duan, Yuanzhao Zhang, Binquan Luan, Jeffrey K Weber, Royce W Zhou, Zaixing Yang, Lin Zhao, Jiaying Xu, Judong Luo, Ruhong Zhou
Examining interactions between nanomaterials and cell membranes can expose underlying mechanisms of nanomaterial cytotoxicity and guide the design of safer nanomedical technologies. Recently, graphene has been shown to exhibit potential toxicity to cells; however, the molecular processes driving its lethal properties have yet to be fully characterized. We here demonstrate that graphene nanosheets (both pristine and oxidized) can produce holes (pores) in the membranes of A549 and Raw264.7 cells, substantially reducing cell viability...
February 20, 2017: Scientific Reports
Fabiana A Gutierrez, Flavio C Bedatty Fernandes, Gustavo A Rivas, Paulo R Bueno
The electronic density of states and its contribution to the capacitance of graphene compounds (oxidized and reduced) were investigated using an electrochemical impedance-derived capacitance spectroscopic approach. It is clearly demonstrated that graphene oxide, which is known to exhibit semiconductor electronic characteristics, has little influence on the magnitude of the measured capacitance. Moreover, when graphene oxide is electrochemically reduced to graphene, the capacitance increases dramatically by about three orders of magnitude (from microfaradays to millifaradays)...
February 20, 2017: Physical Chemistry Chemical Physics: PCCP
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