Hybrid, organic and bio-materialsP
Carbon materials: surface chemistry and biomedical applications
Carbon materials (including diamond, diamond nanoparticles, CNT, graphene, carbon dots, etc.) are the best platforms for new materials research and bioelectronics realization since they offer exceptional properties with nearly perfect interfaces for bio-chemical sensors or for medical applications.
This symposium focuses on theoretical and experimental aspects of surface chemistry of carbon materials (diamond, diamond NPs, graphene, CNTs, carbon dots, etc.) as well as their biochemical and medical applications.
Surface terminations and reactions of carbon materials with different molecules (organic linkers, biomolecules, metals, etc.) will be addressed. Specific surface treatments to get homogeneous surface terminations (e.g. H-term or selective C-O term) applied to bulk or nanocarbons (diamond NPs, CNT, graphene, and carbon dots) are concerned. Techniques used for the carbon materials surface modification can be from spontaneous bonding to photochemical attachment, electrochemical grafting, to Suzuki-coupling of aryl molecules. Special attention will be drawn to mechanisms driving bonding kinetics (e.g. electron transfer reactions, hydrogen cleavage reactions by nucleophilic molecules), and growths schemes (e.g. two-dimensional chain reactions or three-dimensional cross-polymerization reactions). Surface terminations, surface defects, surface roughness and atomic arrangements of surface carbon atoms will be discussed to elucidate bonding mechanisms. Approaches to avoid agglomeration of nanocarbons during surface functionalization will be of particular interest.
Basic understanding from atomic/molecular level to macroscopic properties of modified carbon related surfaces will be hot topics in this symposium. The symposium will especially focus on interface properties of carbon materials after grafting either with linker molecules or complex functionalized surfaces with therapeutic molecules, DNA, proteins and enzymes. Electrochemical applications of modified surface and novel detection schemes using nanocarbon will be included.
Applications of functionalized nanocarbons as biomarkers and for drug delivery and for cancer diagnosis and therapy will be highlighted. Discussion on the toxicity of nanocarbons and contributions dealing with core-shell architectures involving carbon materials will be discussed.
Hot topics to be covered by the symposium:
- Theory and simulation of surface chemistry of nanocarbons
- Surface terminations of nanocarbons
- Surface characterizations of nanocarbons
- Adsorption of biomolecules to carbon surface
- Interfaces of composites of nanocarbon with other materials
- Solution-processed chemistry of nanocarbons
- Electrochemistry of nanocarbons
- Surface modifications of carbon materials
- Electrochemical applications of modified carbon materials
- Biochemical applications of carbon materials
- Medical applications of nanocarbons asbiomarkers and for drug delivery
- Novel sensing principles on carbon surface
- Toxicity of carbon nanocarbons
Proceedings will be published in Physica Status Solidi (a).
Institute of Materials Engineering
University of Siegen
Phone: +49 271 740 2298
Fax: +49 271 740 2442
Bâtiment 451, Point Courrier 45
91191 Gif sur Yvette cedex
Phone: +33 169087102
Fax: +33 169087819
199 Ren-Ai Road, Bldg 910, Room 405
Suzhou 215123, Jiangsu
Phone: +86 51265882036
Fax: +86 51265882846
Olga A. Shenderova
Head of laboratory
International Technology Center
8100 Brownleigh Dr., S120
Raleigh, NC 27615
Phone: +1 9198810250 226
Fax: +1 9198810440
Shiga University of Medical Science
Seta, Otsu 520-2192
Phone: +81 775482102
Fax: +81 775482405
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Authors : T. Petit1, H. A. Girard1, C. Gesset1, M. Combis-Schlumberger1, O. Shenderova2, A. Koscheev3, I. Vlasov4, M. Sennour5, J. C. Arnault1
Affiliations : 1CEA, LIST, Diamond Sensors Laboratory, France 2 International Technology Center, USA 3Karpov Institute of Physical Chemistry, Moscow, Russia 4General Physics Institute, RAS, Moscow, Russia 5Mines Paris, Paristech, France
Resume : Surface graphitized nanodiamonds (NDs) have exceptional chemical reactivity but may potentially exhibit higher toxicity than oxidized NDs due to sp2 reconstructions. Bi-functional NDs simultaneously covered by sp2 reconstructions and oxygen groups may offer a good compromise toward biomedical applications. A possible strategy to prepare bi-functional NDs would be to combine ozone treatments and annealing under vacuum. The stability of ozone-treated detonation NDs with respect to graphitization under vacuum was therefore investigated. NDs first underwent an ozone purification treatment (ND-ozone) by New Technologies (Chelyabinsk) with experimental conditions previously reported . As received detonation NDs from Nanocarbon Research Institute (ND-NRI) disaggregated to primary particles were used as comparison. Both sets were simultaneously annealed during 1 h at 750°C under 5.10-6 mbar. Such thermal treatment was efficient to induce the formation of fullerene like reconstructions on as received NDs as shown by High Resolution Transmission Electron Microscopy (HRTEM). Surface chemistry and crystalline structure of both NDs sets were studied by X-ray Photoemission Spectroscopy (XPS), HRTEM, Thermal Desorption Mass Spectrometry (TDMS) and Raman spectroscopy. From Raman and TDMS data we conclude that reconstructed surface area in annealed ND-ozone is at least 2 times higher than in ND-NRI. After annealing under vacuum, a strong oxygen adsorption occurs on NDs exposed to ambient conditions. The stability of these oxygen groups as well as possible groups left on the surface after 750oC treatment was first investigated by in situ sequential annealings (400°C, 600°C) followed by XPS analyses. More detailed data were collected using TDMS from 100°C to 1000°C. According to TDMS experiments, oxygen groups formed on reconstructed surface are more abundant in ND-ozone than in ND-NRI. Possible reasons of this difference will be discussed. References  Shenderova et al, J. Phys. Chem. C (2011) 9827.  Petit et al, Nanoscale 21 (2012) 6792.
Authors : Marina Massaro, David T Hinds, Frederico Baptista, Andrew Barker and Susan J. Quinn
Affiliations : School of Chemistry and Chemical Biology, University College Dublin, Ireland
Resume : The biocompatibility of carbon nanomaterials offers potential biomedical applications in biosensing, imaging and drug delivery. Carbon nanohorns are particles of between 50-100 nm in size formed from the aggregation of small nanotubes with closed ends, which protrude from a central core. The particles are both non-toxic, robust and possess high surface areas that can be readily functionalized. These combined properties make them excellent candidates for drug. In this study we present results on the binding interactions of carbon nanohorns with small molecules, including drug analogues. Surface modification of the nanohorns has been performed and characterized by Raman spectroscopy and nanoparticle integrity post functionalisation is confirmed by light scattering and microscopy. UV-visible and emission spectroscopic binding studies under a variety of buffer conditions are reported. The titrations reveal a very high affinity for a series of porphyrin molecules through non-covalent interactions and provide insight into the role of surface modification on the loading capacity. Energy transfer at the surface was probed by transient spectroscopy. The reversible nature of the binding paves the way for the application of these particles for drug delivery while the dual modification with luminescent molecules offers the potential for imaging. These initial results provide a quantitative assessment of their binding interactions which is essential to future applications.
Authors : Yinchan Luo, Yonghui Wang, Ting Wang, Jia Tang, Xiaofang Tan, Qian Chen, Zhuang Liu, Rui Peng
Affiliations : Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, Jiangsu, P. R. China
Resume : Graphene oxide (GO), a member of the SP2 carbon nanomaterials family, has drawn huge attention in the past a few years, especially its great potential in biological fields. As more and more biomedical applications of GO (and its derivatives) been explored, critical issues as their biosafety and biological effects arise and must be addressed before any further massive applications. My group is currently working on the biological effects of GO and its derivatives. In our recent work, we fabricate two types of GO-based nanomaterials: a series of GO-Ag nanocomposites (GO-Ag) with different AgNPs to GO ratios, and a series of PEGlyated GO (GO-PEG) with different PEG contents. The effects of GO-Ags and GO-PEGs on two bacteria species, the Gram-negative (G-) bacteria Escherichia coli (E. coli) and the Gram-positive (G+) bacteria Staphylococcus aureus (S. aureus), have been carefully investigated. We discover that, compared to AgNPs, GO-Ag nanocomposite with an optimal ratio of AgNPs to GO is much more effective and shows synergistically enhanced, strong antibacterial activities at rather low dose (2.5 μg/mL). Interestingly, one type of GO-PEG in particular, shows no antibacterial activity at all, but rather an opposite effect, i.e. significantly accelerated bacteria growth. Such effects are further investigated. Our results reveal that GO-Ag interacts with E. coli and S. aureus through distinct, species-specific mechanisms: it functions as a bactericide against the G- E. coli through disrupting bacterial cell wall integrity, whereas it exhibits bacteriostatic effect on the G+ S. aureus by dramatically inhibiting cell division. In the case of GO-PEG, it promotes bacteria growth by interact with bacteria and increase their DNA synthesis. Such interactions can be regulated through and are closely associated with the surface/interface chemistry of the GO-Ag and GO-PEG. Although future work is required to further understand the molecular mechanisms behind these biological effects, our work not only highlight the great promise of GO and its derivatives in regulating microbial growth (GO-Ag as a highly effective antibacterial agent, while GO-PEG as a potential accelerator in fermentation engineering), but also provide more in-depth understandings of the interactions between microorganisms and GO-based nanomaterials.
Carbon dots I : Minfang Zhang
Authors : Yuwu Chi, Chen Zhou, Yongqiang Dong, Ruixue Wang, Xiaomei Lin
Affiliations : Department of Chemistry, Fuzhou University
Resume : Carbon-based dots (CDs), emerging luminescent nanomaterials, usually include carbon nanoparticles of less than 10 nm in diameter (so-called carbon quantum dots, CQDs) and graphene nanosheets of usually less than 100 nm in laterial size (so-called graphene quantum dots, GQDs). CDs not only exhibit many fascinating optical properties, such as photoinduced electron transfer, photoluminescence and electrochemiluminescence, but also present some additional advantages over the heavy metal-containing semiconductor-based quantum dots, such as chemical inertness, good stability, biocompatibility, low toxicity, easy preparation and environmental friendliness. Recently, we have prepared various CDs with different physicochemical properties, such as fluorescence, electrochemiluminescence and luminescence from carbon materials such as graphite rods, activated carbon, carbon black by Top-down method or from some organic precursors such as citric acid, citric acid/polyamines, citric acid/amino acid and EDTA by Bottom-up routes. Based on the investigation of the physiochemical properties of the prepared CDs and their chemical reactions, new types of chemical sensors have been developed for sensing anions, cations, H2O2, O2, glucose, and amino acids in aqueous solutions, and NO2, Cl2 molecules in gas samples. These studies show promising applications of CDs in chemical sensing.
Authors : Matteo Calvaresi, Francesco Zerbetto
Affiliations : Dipartimento di Chimica G. Ciamician, Alma Mater Studiorum Università di Bologna, Via F. Selmi 2, 40126 Bologna, Italy
Resume : The integration of carbon nanoparticles (CNPs) with proteins to form hybrid functional assemblies is an innovative research area with great promise for medical, nanotechnology, and materials science. The comprehension of CNP/protein interactions requires the still-missing identification and characterization of the binding pocket for the CNPs. Using Lysozyme (LSZ) and C60 as model systems along with NMR chemical shift perturbation analysis, a protein/CNP binding pocket is identified unambiguously, for the first time, in solution and the effect of the binding, at the level of the single amino acid, is characterized by a variety of experimental and computational approaches. NMR provide high-resolution information on protein structure and its changes in protein/CNP complexes in aqueous solution. Spectroscopical analysis shows that lysozyme forms a stoichiometric 1:1 adduct with C60 that it is dispersed monomolecularly in water. Circular dichroism indicates that LSZ maintains its tridimensional structure upon interaction with C60. Chemical Shift Perturbation (CSP) analysis confirms that the 3D structure remains largely unaffected by binding, and only a few well-identified residues are perturbed. The CNP recognition is highly specific and localized in a well-defined pocket. Enzyme activity assays show that C60@LSZ retains 53% of activity of the free enzyme.
Authors : Maria Letizia Terranova
Affiliations : Department of Chemical Science and Technology, University di Rome Tor Vergata, Via della Ricerca Scientifica, 00133 Rome, Italy
Resume : Scientifica, 00133 Rome, Italy The issue of creating color centers in diamond has raised in recent years a great attention , being these stable optical diamond defects suitable for a series of bio-related applications. Among the fluorescent defects , those related to Si offer a series of advantages that make them suitable for advanced bio-applications. In particular the SiV color centers provide fast and narrow fluorescence emission in the NIR region, avoiding the overlap with the natural fluorescence of biological objects . However the currently used fabrication methods present drawbacks that hamper the possibility to produce reasonable amounts of fluorescent diamond with spatially localized SiV . The settling of innovative chemical routes can thus be considered a hot topic because of the potential technological impact of such material. This contribution describes two different routes for efficient and spatially selective formation of Si vacancy complex . Both the proposed methodologies provide insertion of Si entities inside the diamond lattice growing by CVD techniques. The first method rely on the deposition of diamond films onto selected areas of lithographed SiO2-NbN substrates and brings to a very intense emission from the SiV in correspondence of the diamond grown on SiO2 compared to that grown on NbN. The formation of Si color centers in diamond grown on pre-definite areas opens a new prospective for the creation of diamond based systems with the co-presence of differently fluorescent defects. Following a second strategy, isolated diamond crystallites or polycrystalline films are grown onto Si substrates preliminarly modified by a treatment with Ni nanoparticles The lowering of the surface tension of the silicon substrate due to the formation of nanosized Si-Ni alloys helps to generate gaseous Si species , promoting the inclusion of Si color centers in the growing diamonds phase . A proper control of the Ni-based treatments enables to obtain highly brilliant single crystals or ultra-bright polycrystalline diamond films , with emission features unimaginable when compared with those obtained using conventional CVD or irradiation methods. Moreover the Ni nanoparticles, acting as localized source of gaseous Si species, could strongly improve the technology for fabrication of localized diamond light sources.The synthesis methodologies developed in our labs enable to successfully generate arrays of diamond with Si color centers and offer practical solutions to the still open problems related to the controlled creation of color centers in diamond .
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Authors : Stephane NEUVILLE
Affiliations : TCE
Resume : Comparison of Raman spectroscopic results is an important aspect of process and device up-scaling engineering for electrochemical energy conversion, especially when more performing ta-C coating materials have to be produced considering its unique outstanding properties. However, Raman spectra achieved with different kinds of carbon materials have shown how much contradictory and confusing those can be when not sufficiently taking into account recently discussed sp3 atomic rearrangement activation effects, the more detailed incidence of stress and material disorder on Raman assignment and some newly revised aspects on Raman fundamentals with which the origin of the so called D disorder and so called 2D peak can be more accurately described. However, this is a matter which is made worse with the number of confusing denomination used for the assignment of carbon material Raman spectra especially involving the denomination D for diamond, D for disorder, D disorder peak which is used in relation with the graphene A-edge vibration mode, (corresponding to a well ordered crystalline structure) and some Raman peak broadening due to second order atomic disorder involving a statistical distribution of interatomic distances, binding energies, and bond orientations. The necessity of clarification on Raman peak designation appears all the more, since different side shoulders of the G peak can be assigned to some aliphatic bonds, atomic point defects and so called odd rings in consequence of used elaboration process producing point defects by ion bombardment, thermal effects and different kinds of atomic rearrangements. Therefore, we propose a new Raman designation nomenclature with which it is intended to reduce confusion and to provide more accurate characterizing of carbon material which especially appears necessary for carbon process optimization during carbon coating engineering.
Authors : Peter Brommer, Alexander Marsden, Neil Wilson, Gavin Bell, David Quigley
Affiliations : Department of Physics, University of Warwick, Coventry, UK
Resume : For many applications it is essential to modify the electronic properties of graphene in a controlled fashion. This can be achieved via oxygen and nitrogen functionalisation in ultra-high vacuum, leading to a system in which electronic and structural properties can be systematically studied. Here we present insights from density functional theory (DFT) calculations on nitrogen and oxygen functionalised graphene systems, such as the low-energy configurations and simulated transmission electron microscopy (TEM) images, binding energies and effective band structures (EBS) of the N and O decorated graphene sheets. We directly compare our results with experiments on graphene grown by chemical vapour deposition (CVD). Angle-resolved photoemission spectroscopy (ARPES - performed at the Antares beamline of Synchrotron SOLEIL, France) resolves the band structure changes on functionalisation, simulated TEM images assist in interpreting low-voltage aberration-corrected TEM measurements, and X-ray photoelectron spectroscopy (XPS) provides information about the chemical environment of the defect atoms. Combined, the computational and experimental techniques provide valuable insights into the effect of functionalisation on the physical and electronic structure of graphene.
Authors : Pavel A. Troshin (1), Ekaterina A. Khakina (1), A. A. Kushch (2) and Jan Balzarini (3)
Affiliations : (1) Institute for Problems of Chemical Physics, Academician Semenov av. 1, Chernogolovka, Moscow region, 142432, Russia, firstname.lastname@example.org (2) D.I. Ivanovsky Institute of Virology of the Ministry of Health and Social Development of the Russian Federation, Moscow, Russia. (3) Rega Institute for Medical Research, Minderbroedersstraat 10, B-3000, Leuven, Belgium
Resume : We present an overview of our studies on the synthesis and investigation of water-soluble fullerene derivatives (WSFs). Chlorofullerenes C60Cl6 and C70Cl8 were shown to be ideal precursors for synthesis of various WSFs. Friedel-Crafts type reactions led to big families of C60 and C70 derivatives bearing appended fragments of arylalkylcarboxylic and aryloxyalkylcarboxylic acids [1-2]. Novel reactions with amines, amino acids , thiols, thioacids  and trialkylphosphites  produced new classes of WSFs. Toxicity and different types of biologycal activity of the prepared WSFs will be discussed. Particular attention will be paid to antiviral activity. It is commonly accepted that anti-HIV action of WSFs is related to the HIV protease inhibition. We will prove with many examples that this belief is not correct in many cases and real target is gp120 which is inhibited efficiently by WSFs. Moreover, examples of WSFs demonstrating appreciable activity against >10 different viruses confirm great potential of using water-soluble nanocarbon materials in biomedicine and drug design. 1 O. A. Troshina, P. A. Troshin, J. Balzarini, et. al. Org. Biomol. Chem., 2007, 5, 2783 2 A. B. Kornev, J. Balzarini, P. A. Troshin et. al., Chem. Commun., 2011, 47, 8298 3 A. B. Kornev, A. A. Kushch, P. A. Troshin et. al. Chem. Commun., 2012, 48, 5461 4 E. A. Khakina, J. Balzarini, P. A. Troshin, et. al. Chem. Commun., 2012, 48, 7158 5 E. A. Khakina, P. A. Troshin et. al. Chem. Commun., 2012, 48, 8916
Authors : Yongfu Lian*,Qin Zhou, Hui Li, Yan Wang
Affiliations : School of Chemistry and Materials Science Heilongjiang University, Harbin 150080, (China)
Resume : Regioselective cycloaddition of admantylidene carbene (1) to Pr@C2v(9)-C82 affords the first derivatives of praseodymium-containing metallofullerenes. Two monoadduct isomers (2a and 2b) were obtained. X-ray crystallographic results of 2a confirm a [5,6]-open structure with multiple metal positions. Theoretical calculations reveal that the negative charges immigrated from the internal metal ion is anisotropically distributed on the cage surface, making one of the cage carbons, which is very close to the metal ion, much more reactive than others. Our study has shed new light on the chemical behaviors of mono-EMFs which are viewed as the simplest prototypes of EMFs. Thus the results will stimulate further investigation on the formation mechanism, the properties and potential applications of these hybrid materials
Authors : Yu-Pu Lin, Younal Ksari, Jai Prakash, Luca Giovanelli, Jean-Marc Themlin
Affiliations : Aix-Marseille Université, CNRS, IM2NP, UMR 7334, 13397 Marseille, France
Resume : The doping of 2D materials, such as graphene, which influences their electronic and chemical properties, is currently a critical aspect in their development. For example, the N-doped graphene has been reported to exhibit superior performance over the pristine material in several applications (field-effect transistors, batteries, fuel cells, super-capacitors, and biosensors). However, methods to realize a reliable and controlled doping have still to be mastered. In this work, we present an effective, versatile plasma-based method for the nitrogen-doping of graphene grown on 6H-SiC(0001). By using a tunable hybrid plasma source, we expose graphene monolayers to a stream of N ions and/or to a neutral flow of thermalized N species. The electronic properties of the N-doped graphene are revealed using angle-resolved inverse photoemission spectroscopy (ARIPES), which reveals its doping level through the analysis of the pi* states dispersion. The results show that low-energy N ions (5~35 eV) cause a n-type doping (up to 0.4 eV) with a majority of graphitic (substitutional) N (up to 8.7%), as revealed by XPS. On the other hand, neutral N species rather form pyridinic-N in the presence of defects. In brief, we show how a simple plasma-based technique can be used in a versatile way to control the bonding environment of N atoms in graphene. It will certainly be of great interest for the processing of future graphene-based nano-devices using widespread technologies like plasma-processing.
Authors : P. Písařík 1,2,*, M. Jelínek 1,2, T. Kocourek 1,2, J. Mikovký 1,2, J. Remsa 1,2, M. Zezulová 1,2, K. Jurek 2
Affiliations : 1 Czech Technical University in Prague, Faculty of Biomedical Engineering, nam. Sitna 3105, 272 01 Kladno, Czech Republic 2 Institute of Physics ASCR v.v.i., Na Slovance 2, 182 21 Prague 8, Czech Republic * E-mail: email@example.com, tel.:+420 312 608 223, fax.: +420 312 608 204
Resume : The mechanical and antibacterial properties of silver doped diamond-like carbon (Ag-DLC) films have been investigated. Ag-DLC were deposited on silicon (Si 100) and titanium substrates (Ti-6Al-4V) by pulsed laser ablation (PLD) for laser energy density 10 J∙cm-2 using KrF excimer laser and segmented target (graphite : silver - 7:1, 3:1, 5:3). The composition was analyzed using wavelength-dependent X-ray spectroscopy. The topology and surface properties as roughness of films were studied using scanning electron microscopy and atomic force microscopy. Mechanical properties of DLC films with various silver content were evaluated. Hardness (reduced Young's modulus) was determined by nanoindentation. Films adhesion was studied using scratch test and with concentration of silver decreasing. In vivo measurement (using gram positive and negative bacteria) of antibacterial properties of the Ag-DLC films. This result opens further possibility for application of Ag-DLC films in medicine.
Authors : Federico Zen, Thomas Duff, M. Daniela Angione, Ronan J. Cullen, James Behan, Eoin M. Scanlan,* Paula E. Colavita*
Affiliations : School of Chemistry, University of Dublin Trinity College, College Green, Dublin, Dublin D2, Ireland
Resume : The ability of surfaces to resist the unspecific adsorption of proteins is thought to provide an important indication about the ability of such surface to resist biofouling Therefore, there has been great interest in the development of coatings or surface modification strategies that allow controlling protein adsorption. We have recently reported on the use of aryldiazonium salt chemistry as a one-step, solution-based method for the glycosylation of carbon surfaces, leading the formation of strongly bound carbohydrate adlayers. Here we report a detailed study of protein adsorption at carbohydrate-modified amorphous carbon surfaces (a-C) using a combination of spectroscopic and contact angle methods. The adsorption of three proteins, bovine serum albumin (BSA), lysozyme (Lyz) and fibrinogen (Fib), from buffer saline solution was investigated using surfaces coated with four different monosaccharides. We show results indicating that the carbohydrate layer significantly reduces surface protein adsorption, particularly in the case of protein concentrations close to physiological values in biologically important fluids (e.g. serum). Surface energy determinations using the OWRK model suggest that changes in surface energy are partly at the origin of the observed antifouling behaviour. Finally, we also show that coatings obtained using more structurally complex carbohydrate aryldiazonium precursors can further reduce protein adsorption by introducing steric repulsion effects.
Authors : S.-M. Iordache(1), A.-M. Iordache(1,*), I. Stamatin(1), A. A. Ciucu(2), E. Fagadar-Cosma(3), R. Cristescu(4)
Affiliations : (1) 3Nano-SAE Research Centre, University of Bucharest, PO Box MG-38, Bucharest-Magurele, Romania (2) University of Bucharest, Department of Analytical Chemistry, Bucharest, ROMANIA (3) Institute of Chemistry Timisoara of Romanian Academy, Department of Organic Chemistry, 300223, Timisoara, Romania (4) National Institute for Lasers, Plasma & Radiation Physics, Lasers Department, P.O. Box MG-36, Bucharest-Magurele, Romania *Corresponding author: firstname.lastname@example.org
Resume : This paper investigates the response of screen printed electrodes (SPEs) based on metallo-porphyrine (Zn, Co and Mn) to biogenic amines (putresceine, cadaverine, histamine etc) extracted from commercial meat samples. The sensitive layer (metallo-porphyrine) was dropcast on the working carbon electrode. Modification of the working electrode with metallo-porphyrine changed the sensing characteristics increasing the oxidation potential for biogenic amines, detecting concentrations down to 0.5 ppm. The SPE have been characterized by AFM spectroscopy and cyclic voltammetry. The modified electrodes presented selectivity towards histamine and were less sensitive towards putresceine and cadaverine. This behavior opens the posibilities for applications both in food safety and medicine.
Authors : A.M.I. Trefilov, L. Popovici, S. M. Iordache, A. Balan, C.E. Serban, I. Stamatin
Affiliations : University of Bucharest, Faculty of Physics, 3Nano-SAE Research Center, Atomistilor 405, P.O. Box 38, Bucharest-Magurele, Romania
Resume : Commonly carbon aerogel is synthesized via sol-gel method in monolith shapes from resorcinol and formaldehyde polymerization in the presence of an acid or basic catalyst. They are brittle compacts with high surface area (500-800 m2/g), porosity (40 80 %), low mass densities (0.1-0.6 g/cm3). This study report a new route of the sol-gel process performed in centrifugal field. The carbon aerogel yield improved properties related to density, porosity, mechanical strength and microporous structure. The polycondensation reaction and gelification are performed at different G- force (30-150 g). The pyrolysis and thermal treatment carried at 800 and 1300 °C led to carbon aerogel in cylindrical shapes with high mechanical strength, density up to 0.6-0.7 g/cm3, specific surface area around of 800m2/g. The electrochemical properties are dependent on the centrifugation and are comparative with carbon paper. Our results demonstrate the correlation between the primary parameters of the centrifugation process (e.g. G-force) and the physical properties (density, pore structure and specific surface area) of the synthesized aerogel. This allows us to control the gel properties in applications of interest: gas diffusion layers in fuel cells, hydrogen adsorption materials, and electrodes in electrochemical energy conversion.
Authors : A. Zubarev*, A.-M. Iordache, I. Stamatin
Affiliations : University of Bucharest, Faculty of Physics, 3Nano-SAE Research Center, Atomistilor 405, P.O. Box 38, Bucharest-Magurele, Romania, 077125 *Corresponding author: email@example.com
Resume : In this study, we investigated a new type of 2D crystals spirographene. A 3D analogue for spirographene is the glitter, predicted in 1994. The topological structure of glitter has been analyzed in several articles. In order to clarify the proprieties we analyzed the structures with reduced dimensions like zero-dimensions effective quantum dots. We proved the most important properties of spirographene and graphene quantum dots: BandGap value, fast excitation energy and its Raman and IR characteristic spectra. With those size dependent characteristics, we further compared these results to graphene and spirographene to obtain the limit of transition from a quantum structure to bulk and calculate the maximum dimensions for a quantum dot. This phenomenon is possible due to the total delocalization of electrons. These results could help steer the new finds towards implementation in technology (energy conversion, storage) and discover new forms of nano-carbon, like spiro-nano-tubes, spiro-nano-corns, etc. Keywords: nano-carbon, spirographene, quantum dots
Authors : A.- M. Iordache(1), A. Zubarev(1,*), S.-M. Iordache(1), S. Stamatin(1,2), I. Stamatin(1)
Affiliations : (1)University of Bucharest, Faculty of Physics, 3Nano-SAE Research Center, Atomistilor 405, P.O. Box 38, Bucharest-Magurele, Romania, 077125 (2)University of Southern Denmark, Campusvej 55, DK-5230 Odense, Denmark *Corresponding author: firstname.lastname@example.org
Resume : The electrical discharge in carbon containing liquids could be a new approach in synthesis of carbon nanoparticles. DC-electrical discharge was carried between two graphite electrodes in: benzene; benzene/toluene, naphthalene in benzene/toluene, decohidronaphthalene, phenol/ decahidronaphthalene and naphthalene/ xilene. During discharge different types of nanocarbon species were obtained and analyzed by SEM/TEM, UV-Vis spectrophotometry, Raman and FTIR Spectroscopy; and DLS. The average diameter of the nanoparticles was 100±5 nm, with various turbostratic structure.. The electrical discharge in carbon containing liquids can be appropriate method to develop new nanocarbon particles with important applications in supercapacitors, nanocomposites or electronic devices.
Authors : I. Stamatin(1,*), A. Zubarev(1), A.- M. Iordache(1), S.-M. Iordache(1), S. Stamatin(1,2)
Affiliations : 1University of Bucharest, Faculty of Physics, 3Nano-SAE Research Center, Atomistilor 405, P.O. Box 38, Bucharest-Magurele, Romania, 077125 2University of Southern Denmark, Campusvej 55, DK-5230 Odense, Denmark *Corresponding author: email@example.com
Resume : The spirographene is an exotic material with unusual properties. The 3D analogue of spirographene is glitter discovered in 1994 by Hoffman. This 2D-material has strong anisotropy and combine metallic, semimetal and semiconductor properties. These properties make it very attractive for numerously applications specially in electronics. This contribution proposes a route for synthesis spirographene using DC electrical discharge in liquids 0 - 1.5 M phenol in decahidronaphthalene (Cis+Trans) In liquor . after synthesis are identified both graphene and spirographene in very low concentrations and nanocarbon. The resulted nanoparticles were analyzed using Raman and FTIR spectroscopy, DLS, UV-Vis spectrophotometry, XRD and HRTEM.
Authors : P. Majzlikova, J. Prasek, M. Elias, O. Jasek, L. Zajickova
Affiliations : Brno University of Technology, Brno, Czech Republic; Brno University of Technology, Brno, Czech Republic; Masaryk University, Brno, Czech Republic; Masaryk University, Brno, Czech Republic; Masaryk University, Brno, Czech Republic;
Resume : Commercially available multi-walled carbon nanotubes (MWCNTs) were functionalized in capacitively coupled radio frequency discharges in Ar/O2 and Ar/cyclopropylamine gas mixtures with the aim to obtain carboxylic (?COOH) and amine (?NH2) functional groups, respectively. The pristine and modified MWCNTs were used for the fabrication of working electrodes of a standard three-electrode electrochemical sensor using spray-coating deposition. The sensors were electrochemically characterized by cyclic voltammetry using ferrocyanide/ferricyanide redox couple and dopamine. Dopamine is one of the most studied compounds with CNTs based sensors due to its electroactivity and biological significance. The electrochemical measurements indicated that the sensors with MWCNTs-based working electrodes were able to detect 2.5 mM solutions of both the studied analytes with a good electrochemical response. The electrocatalytic activity of the MWCNTs-based working electrodes towards the electrochemical oxidation of ferrocyanide and dopamine was associated with the MWCNTs functionalization in the following order: carboxyl-containing MWCNT > amine-containing MWCNT > pristine MWCNTs. The values of the oxidation peak currents determined using two samples of modified and one sample of pristine MWCNTs in the solution of 2.5 mM potassium ferrocyanide and potassium ferricyanide in the 0,1M KCl and in the solution of 2.5 mM dopamine in 0.01M HCl were in the range 30 - 54 uA and 86 - 99 uA, respectively.
Authors : T Miyamoto(1) , H Nagasaka(2) , T Shimizu(1) , Y Teranishi(2) , T Watanabe(2) , M Yang(1)
Affiliations : (1) Tokyo Metropolitan University, 1-1, Minami-Osawa, Hachioji, Tokyo, Japan; (2) Tokyo Metropolitan Industrial Technology Research Institute, 2-4-10, Aomi, kotoku, Tokyo, Japan
Resume : High-over-potential for oxygen evolution with chemical stability of boron doped diamond (BDD) electrodes has been expected for various industrial applications such as ozone water purification and effluent water treatment. However, because of its high production cost for BDD electrodes, the industrial scale application has not been widely spread. To reduce the production cost of BDD electrodes and to deposit the BDD thin films on a large area, hot filament chemical vapor deposition (HFCVD) equipment was designed by authors. The high deposition rate of 3 5 μm/h, and the large area deposition was succeeded for a none-doped diamond films using CH4, H2 as source gases. In the present study, to achieve the high-rate synthesis of BDD thin films, trimethyl borate (B(OCH3)3) was additionally introduced to this HFCVD system as a dopant. The flow rate of trimethyl borate and the filament-substrate distance, which plays a significant role on the deposition rate and the crystallinity of the films, was precisely adjusted. Based on the scanning electron microscopy (SEM) observation, the X-ray diffraction (XRD) and the Raman spectroscopy analysis, and the cyclic voltammetry (CV) measurement in H2SO4, the crystallinity and the electrochemical performances of the high-rate synthesized BDD films was investigated. As results, the BDD films with a growth rate of higher than 2 m/h was obtained and it showed a wide potential window. The appropriate gas composition and filament-substrate distance under higher rate synthesis of BDD films was discussed in view of the BDD film growth rate and its crystallinity.
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Diamond : Xin Jiang
Authors : Naoki Komatsu, Li Zhao, Takahide Kimura
Affiliations : Shiga University of Medical Science
Resume : Biomedical applications of nanodiamond (ND) have been investigated extensively due to its low toxicity, non-bleaching fluorescence, and high extensibility of the surface functionality through covalent organic functionalization. For in vivo applications such as drug carrier and imaging probe, ND should form a stable hydrosol under a physiological environment. In this context, we recently found that polyglycerol (PG) functionalization is very effective to impart the sufficient solubility and stability to ND . In addition, the stable hydrogel of PG-functionalized ND (ND-PG) enabled precise characterization of the chemical structure by solution phase NMRs. Quantitative analyses were also conducted by elemental and thermogravimetric analyses. The ND-PG was subjected to further organic transformations at a number of hydroxyl groups on the PG layer to add more functions. As a result, we successfully prepared the ND-based drug carrier with acid-responsive platinum drug  and MR imaging probe with gadolinium  and applied them to in vivo and in vitro evaluations.  L. Zhao, N. Komatsu, Angew. Chem. Int. Ed., 50 (6), 1388-1392 (2011)  L. Zhao, N. Komatsu, X. Chen, submitted  L. Zhao, N. Komatsu, J. Nanosci. Nanotechnol. in press
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Authors : GuanLin Chen, Wei-Hung Chiang
Affiliations : Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, 10607, Taiwan
Resume : Recent theoretical  and experimental  studies have suggested that heteroatom-doped carbon nanomaterials such as carbon nanotubes (CNTs) and graphenes as novel materials with exceptional properties for applications including nanoelectronics, energy storage, fuel cells, and electrochemical sensing. However, current synthesis methods of heteroatom-doped carbon nanomaterials usually involve complicated vacuum systems, making it difficult to enable industrial-scale production . Consequently, the development of a controllable synthesis of heteroatom-doped carbon nanomaterials at atmospheric pressure will lead to important advances on both scientific studies and innovation applications. Here we demonstrate an atmospheric-pressure carbonthermic method to produce boron-doped CNTs (BCNTs) and boron-doped graphenes (BGs) with tunable boron atomic concentration ranging from 0.4 to 21.1 atomic percentage (at%). Systematic X-ray diffraction and X-ray photoelectron spectroscopy characterizations indicated that boron atoms were successfully doped into the sp2 graphene lattice of CNTs and graphenes. Detailed high-resolution transmission electron microscopy electron energy loss spectroscopy (HRTEM-EELS) revealed that boron substitution doping mainly occurred on the CNT surface. It is also noteworthy from a practical point of view that the developed atmospheric-pressure synthesis method is amenable to industrial-scale production since it avoids the need for a vacuum system.
Authors : Paula E. Colavita, Michael E.G. Lyons, Deirdre M. Murphy, Ronan J. Cullen, Dilushan R. Jayasundara, Stefania Marzorati, Richard L. Doyle
Affiliations : School of Chemistry and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, College Green, Dublin 2, Ireland
Resume : Carbon materials are highly versatile and find numerous applications in areas as diverse as analytical chemistry, energy research and biomaterials. Effective control over carbon interfacial properties is often critical in order to achieve their desired performance in these applications. In this contribution we discuss our progress on the development of structure-activity relationships in amorphous carbons, aimed at understanding the interplay between carbon properties and interfacial charge transfer. We synthesized a range of amorphous carbon thin films via magnetron sputtering and post deposition thermal annealing and characterized them using a combination of spectroscopic and electrochemical methods. We report on quantitative in situ studies of the rate of spontaneous reactions initiated by charge transfer processes using aryldiazonium salts, via nanogravimetry; our results show that the carbon composition can affect both rates and mechanism in these reactions. Also, we report on photoelectron spectroscopy studies of the carbon valence electronic structure and correlate these results to experimentally determined rates of heterogeneous charge transfer at the carbon-solution interface in spontaneous reactions with aryldiazonium salts and in potential driven reactions with outer-sphere redox species. Finally, we discuss the use of Marcus-theory based models for the interpretation of interfacial reactions and charge transfer rates at amorphous carbon surfaces.
Authors : Amadou L. Ndiaye1,2, Christelle Varenne1,2, Jérôme Brunet1,2, Abhishek kumar1,2, Alain Pauly1,2
Affiliations : (1) Clermont Université, Université Blaise Pascal, Institut Pascal, BP 10448, F-63000 Clermont-Ferrand, (2) CNRS, UMR 6602, Institut Pascal, F-63171 Aubière,
Resume : As member of the wide family of carbon materials, the carbon nanotubes (CNTs) offer remarkable properties. These properties are closely related to: i) their nature (narrow size) leading to high specific surface area and ii) their surface chemistry (functionalization abilities) providing tuneable properties for design materials. These features , in combination with their electronic properties are preliminary requirements for sensor material. As a consequence, CNTs are a judicious choice for the development of efficient gas sensors. To be useful and processable in solution, CNTs need first to be chemically or physically modified to overcome their lack of solubility. In this context, non-covalent functionalisation offers the possibility to render the CNTs processable in solution while keeping their electronic properties. More especially, we have developed sensitive material based on CNTs with porphyrins or phthalocyanines as functionnals groups for BTX (benzene, Toluene, Xylenes) detection. Moreover, the dispersions of raw CNTs were also optimized for NO2 and O3 detection. The sensing materials synthesized and characterized by standard techniques (UV-Vis spectroscopy, TGA, TEM, Raman analysis) and sensors response were established by means of resistive and QCM (Quartz Crystal Microbalance) transducers. References:  A. Krueger, Carbon Materials and Nanotechnology, Wiley-VCH Verlag, 2010, 123.  S. Liu et.al., Coord. Chem. Rev. 254/9-10 (2010) 1101.
Authors : Jeong Gon Son
Affiliations : Photo-electronic Research Center, Korea Institute of Science and Technology, Seoul, Republic of Korea
Resume : Graphene has great interests because of its incredible electronic and thermal properties for the potential future electronic devices and energy application. However, their intrinsic zero bandgap property and high thermal conductivity are fairly hard to perform the high on-off current ratio of field effect transistor and application to thermoelectric devices. For the overcoming this huddle, graphene nano-strucrues with sub-10 nm scales for the quantum confinement was suggested and showed opening bandgap and high on-off ratio experimentally. However, to achieve a high driving current for the practical device application, densely aligned graphene nano ribbon array should be required. A block copolymer is well-known material for the straightforwardly developing nano-sized pattern from sub-10 nm to 100 nm on large area through the self-assembly. We has investigated highly aligned sub-10 nm pattern formation from polystyrene-block-polydimethylsiloxane (PS-b-PDMS) block copolymer, which is representative for the high block copolymers, and their complex patterns to the application to practical devices. In this presentation, we mainly show sub-10-nm graphene nano-ribbon array field effect transistors which fabricated by cylindrical PS-b-PDMS block copolymer line patterns as a lithographical template on chemical vapor deposition (CVD) grown graphene monolayer sheets. We also briefly introduce graphene nanomesh structures for improving thermoelectric properties.
Authors : Karolina Z. Milowska, Magdalena Woińska, Małgorzata Wierzbowska,
Affiliations : 1)Photonics and Optoelectronics Group, Ludwig-Maximilians-Universität München, Amalienstr. 54, D-80799 Munich, Germany 2)Nanosystems Initiative Munich (NIM), Schellingstr. 4, D-80799 Munich, Germany; Faculty of Chemistry, University of Warsaw, ul. Pasteura 1, PL-02-093 Warszawa, Poland; Faculty of Physics, University of Warsaw, ul. Hoza 69, PL-00-681 Warszawa, Poland
Resume : We present results of extensive and systematic studies of the mechanical and electronic properties of B- and N-doped graphene(G). The Youngs(Y), bulk(K), and shear(S) moduli and Poisson's ratio(P) have been calculated by means of density functional theory for a representative set of supercells with disordered impurity patterns including aggregates. The structure and related electronic properties of doped G have been investigated on the basis of simulated STM images and differential charge densities presenting sample morphology. Elastic properties are strongly related to the electronic properties of doped systems, especially for heavily doped samples. Local arrangements of dopants, aggregation or separation of impurities play crucial roles in establishing of stiffness in the investigated systems. Interestingly, these findings are different for B- and N-contained samples. We claim that some way of incorporating N in the G layer could even strengthen the doped system in comparison to the pure G. Notably, incorporation of B induces large structural and morphological changes seen in simulated STM images and reduces the stiffness. Y and S increase or decrease with the doping concentration for N or B, respectively, while K and P exhibit opposite trends. We also show how to relate STM measurements with mechanical quality factors in B- and N-doped G, which can be utilized in engineering of graphene-based devices. K.Z.Milowska,M.Woińska,M.Wierzbowska J.Phys.Chem. C117(39),20229(2013)
Authors : Naoki Komatsu, Gang Liu, Takahide Kimura
Affiliations : Shiga University of Medical Science
Resume : We have been developing host-guest methodology for separation of single-walled carbon nanotubes (SWNTs) according to the handedness and diameter with gable-type chiral diporphyrins, designated as diporphyrin nanotweezers, consisting of two porphyrins and rigid spacer in between [1-13]. In this paper, we will talk about next generation of the host molecules focusing on larger diameter of SWNTs, named ?nanocalipers?.  X. Peng, N. Komatsu, S. Bhattacharya, T. Shimawaki, S. Aonuma, T. Kimura, A. Osuka, Nature Nanotechnology, 2, 361-365 (2007)  G. Liu, F. Wang, S. Chunchaiyakul, Y. Saito, A. K. Bauri, T. Kimura, Y. Kuwahara, and N. Komatsu, J. Am. Chem. Soc., 135, 4805-4814 (2013)  G. Liu, A. F. M. M. Rahman, S. Chaunchaiyakul, T. Kimura, Y. Kuwahara, and N. Komatsu, Chem. Eur. J., 19, 16221-16230 (2013)  F. Wang, K. Matsuda, A. F. M. M. Rahman, X. Peng, T. Kimura, and N. Komatsu, J. Am. Chem. Soc., 132, 10876-10881 (2010).
Authors : Gan Jia, Wen Zhang, Yanfang Gao*
Affiliations : College of Chemical Engineering, Inner Mongolia University of Technology
Resume : Dimethyl carbonate (DMC) is used as an important building block in fine and bulk chemical industry. It is commonly prepared by phosgenation, oxidative carbonylation, transesterification and urea methanolysis in large-scale production. Our group developed a unique electrochemical system to overcome the problems existed in above well-established methods. To date, the majority of the known homogeneous catalysts for the electro-synthesis of DMC are based on noble metal salts and transition metal N-donor complexes. However, exorbitant cost and poor recycling of the catalysts limited its applications. Our previous study has shown that MOF could be used as heterogeneous catalyst for synthesis of DMC. Based on these investigations, this time we reintroduced a MOF/GO hybrid material used for the electrocatalytic process. The XRD result suggests that the presence of GO did not have any noticeable impact on the formation of the crystalline frameworks. A smaller size of the block structure and more dispersed blocks than MOF alone were observed after the introduction of graphene oxide. No distinct redox peaks were observed before and right after the addition of hybrid electrocatalysts. However, as the reaction proceeded, a couple of nearly reversible redox peaks were obtained from the cyclic voltammograms.
Authors : Anton Manakhov, Lenka Zajicková, Petr Skladal, Jan Cechal
Affiliations : Plasma Technologies, Central-European Institute of Technology, Masaryk University; Department of Physical Electronics, Faculty of Science, Masaryk University; Research group Nanobiotechnology - Centre for Structural Biology - Central-European Technology Institute; Central-European Institute of Technology, Brno University of Technology
Resume : Biosensors have been extensively developed and applied for biomedical and environmental study. Although there are many different types of biosensing techniques, all these methods require immobilization of biomolecules (DNA, antibody, enzyme) onto the sensor surface. The bio-molecule immobilization step is critical in the development of any sort of biosensor, as it can affect operational properties of the sensor. For many years self-assembled monolayers (SAMs) of alkanethiolates have been widely used for functionalization of the gold surfaces, in spite of low stability of the S-Au linkage at higher temperature or UV radiation. One of the most suitable candidates to substitute SAMs for sensing surface modification is the plasma polymerization providing thin functional films. Among various functional plasma coatings, the amine-rich films are extensively employed for numerous biomedical applications, thanks to the reactivity of the introduced primary amine groups. In this work, cyclopropylamine plasma polymerization is employed to deposit stable amine thin films on the surface of quartz crystal microbalance (QCM) biosensors. The antibody specific to human serum albumin (anti-HSA) is attached to the QCM surface via crosslinkage obtained by intermediate reaction with glutaraldehyde. All steps of the bio-immobilization are controlled by XPS and FT-IR to characterize surface and layer(bulk) chemistry. The stability of the deposited coating during immobilization and within biosensor
Authors : Maria A. Gunawan(1,3), Didier Poinsot(1), Bruno Domenichini(2), Peter R. Schreiner(3), Jean-‐Cyrille Hierso(1,4)
Affiliations : Université de Bourgogne, (1) Institut de Chimie Moléculaire (UMR-‐CNRS 6302) et (2) Laboratoire Interdisciplinaire Carnot de Bourgogne (UMR-‐CNRS 6303), Dijon, FRANCE (3) Justus Liebig Universität, Institut für Organische Chemie, Giessen, GERMANY (4) Institut Universitaire de France (IUF) E-‐mail: jean-‐cyrille.hierso@u-‐bourgogne.fr
Resume : Nanometer size particles having a perfect diamond cubic lattice are fascinating molecules which have recently shown applications that span the fields of organic and inorganic chemistry, physics, materials science, bioengineering, medicine and beyond.[1-‐3] The term diamondoid has been used to name cage hydrocarbon molecules that are totally or mostly superimposable on the diamond lattice; in this context nanodiamonds are unique forms of (C,H)-‐based nanostructures best described as fully hydrogen-‐ terminated diamonds of nanometric size. In addition to their perfectly defined chemical formula and structure, diamondoids can be selectively functionalized in determined positions (Scheme 1).[4, 5] We aim to build hybrid materials from multilayer diamondoid/metal deposition: applications in catalysis, optics and electronics are envisaged. In this purpose, several methods of vapor deposition, including physical vapor deposition (PVD), chemical vapor deposition (CVD), and sublimation at atmospheric pressure (APS) are explored. After having determined the vapor pressure curves of several functionalized and native nanodiamonds, we achieved the deposit of 1-‐hydroxydiamantane (1) by physical vapor deposition (PVD) under strictly anaerobic and low-‐pressure conditions (1.4x10-‐6 mBar). The deposits were characterized by XPS and SEM, showing typical hexagonal structures growth. Similarly, other functionalized-‐diamondoids, such as 4-‐fluorodiamantane (2), have been deposited under atmospheric pressure, demonstrating that depending on the functions present on the diamond the general structure of the discrete deposits at the micro and nanometer scale can vary dramatically and can be controlled from the deposit conditions. References  Schwertfeger, H.; Fokin, A. A.; Schreiner, P. R. Angew. Chem. Int. Ed. 2008, 47, 1022-‐1036.  Kruger, A. Adv. Mater. 2008, 20, 2445.  Mochalin, V. N.; Shenderova, O.; Ho, D.; Gogotsi, Y. Nat. Nanotechnol. 2012, 7, 11.  Fokina, N. A.; Tkachenko, B. A.; Merz, A.; Serafin, M.; Dahl, J. E. P.; Carlson, R. M. K.; Fokin, A. A; Schreiner, P. R. Eur. J. Org. Chem. 2007, 4738-‐4745.  Schwertfeger, H.; Würtele, C.; Hausmann, H.; Dahl, J. E. P.; Carlson, R. M. K.; Fokin, A. A; Schreiner, P. R. Adv. Synth. Catal. 2009, 351, 1041-‐1054.
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Carbon Dots II : Pavel Troshin
Authors : Lei Bao, Cui Liu, Zhi-Ling Zhang, Jing-Ya Zhao, Dai-Wen Pang*
Affiliations : Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, and State Key Laboratory of Virology, Wuhan University, Wuhan, 430072, P. R. China
Resume : Tuning the photoluminescence (PL) of carbon nanodots(C-dots) remains a big challenge. In this communication, we demonstrate that the PL of C-dots, as a function of surface-state transitions, can be tuned via changing their size or the extent of surface oxidation. Increasing the size or surface oxidation of C-dots results in reducing the energy gaps of surface states; hence, the large-sized C-dots or the C-dots with high surface-oxidation degree are of long-wavelength fluorescence emissions. Experimentally, this proposed strat-egy can be realized reproducibly by varying the reaction con-ditions, e.g. the reaction time, temperature and concentra-tion of reactants in the preparation of C-dots through oxida-tion of carbon fibers in nitric acid solution. Accordingly, the emissions of fluorescent C-dots have been continuously tuned from 430 nm to 610 nm. This work provides a strategy to intentionally tune the PL properties of C-dots and facili-tates the understanding of their fluorescence mechanism as well.
Graphene III : Vincenzo Palermo
Authors : Haifeng Dong, Wenhao Dai, Xueji Zhang
Affiliations : Beijing Key Laboratory for Bioengineering and Sensing Technology, University of Science & Technology Beijing
Resume : Zero dimension graphene quantum dots (GQDs) with smaller lateral dimensions and abundant periphery carboxylic groups exhibits unique fluorescence properties, good biocompatibility and much reactive sites for functionalization, thus providing a great promising applications in gene delivery and cell imaging. Here, a simple and multiple functional nanocarrier of polyethylene glycol(PEG)/poly(L-lactide) (PLLA)-grafted GQDs was proposed. The functionalization of GODs with PEG/PLLA imparts the nanocomposite excellent biocompatibility and superb transfection efficiency of gene probe for micorRNA (miRNA) detection, while the fluorescence of GQDs provides an effective pathway for live cell imaging. Furthermore, simultaneous loading of multiple gene probes on the large specific surface area via ππ stacking and hydrophobic interactions is investigated. Compared to loading with single gene probe, remarkably higher anti-cancer activity was observed from the combined loading. Considering the good biocompabilty, high tranfection efficiency, intrinsic optical properties and large specific surface area for combined loading, the proposed NGO-based nanocarrier is a promising material and may find widespread biological and medical applications.
Authors : S.A. Usmanova, G.A. Holmatova, D. Nuritdinov, A.P. Mukhtarov, K.M. Abdiraimova
Affiliations : S.A. Usmanova, G.A. Holmatova, D. Nuritdinov, National University of Uzbekistan, 100214 Tashkent, Uzbekistan; A.P. Mukhtarov, Institute of Nuclear Physics AN RUz, 100214 Tashkent, Uzbekistan; K.M. Abdiraimova, Tashkent Institute of Railway Engineering, 100214 Tashkent, Uzbekistan
Resume : The revealing carbon and silicon nanoparticles discovered wide possibilities to use them as hydrogen gas accumulators in energy industry and transportation. The main problem of the storage and safe transportation of the hydrogen gas in industry can be resolved by using carbon and silicon nanotubes which adsorbs the hydrogen gas inside the tube. One of the problems in hydrogen storage in nanomaterials is the hydrogen reverse extraction from nanopores and nanotubes. Extraction of the hydrogen from the nanomaterial can be produced by heating or another effect. However, despite of researchs in this area, the state of hydrogen inside the nanotubes and the effect on the physical properties of the tubes have so far not been studied in detail. In this work the position of hydrogen atoms and molecules in carbon and silicon nanoparticles of different sizes and configurations, as well as its impact on the nanoparticles spatial and electronic structure were researched by quantum chemical methods as HF, DFT, MD and DTBM. Also, the nature of π-electron delocalization in various nanostructures of carbon and silicon clusters as clusters, fullerenes, nanotubes and graphene was studied.