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Surface chemistry

Felix Lampert, Shima Kadkhodazadeh, Takeshi Kasama, Kristian Vinter Dahl, Alexander Bruun Christiansen, Per Møller
Hydrogen silsesquioxane ([HSiO3/2]n) based "spin-on-glass" has been deposited on 316L substrate and cured in Ar/H2 gas atmosphere at 600 ºC to form a continuous surface coating with sub-micrometer thickness. The coating functionality depends primarily on the adhesion to the substrate, which is largely affected by the chemical interaction at the interface between the coating and the substrate. We have investigated this interface by transmission electron microscopy and electron energy loss spectroscopy...
February 19, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Lisa M Housel, Lei Wang, Alyson Abraham, Jianping Huang, Genesis D Renderos, Calvin D Quilty, Alexander B Brady, Amy C Marschilok, Kenneth J Takeuchi, Esther S Takeuchi
Future advances in energy storage systems rely on identification of appropriate target materials and deliberate synthesis of the target materials with control of their physiochemical properties in order to disentangle the contributions of distinct properties to the functional electrochemistry. This goal demands systematic inquiry using model materials that provide the opportunity for significant synthetic versatility and control. Ideally, a material family that enables direct manipulation of characteristics including composition, defects, and crystallite size while remaining within the defined structural framework would be necessary...
February 19, 2018: Accounts of Chemical Research
Lanqun Mao, Hailong Yan, Shuyue Guo, Fei Wu, Ping Yu, Huibiao Liu, Yuliang Li
Graphdiyne (GDY), a new kind of 2D carbon allotrope consisting of sp- and sp2-hybridized carbon atoms, has been envisaged to be promising in fundamental studies and various applications due to their unique atomic arrangement and electronic structure as well as surface chemistry. We herein for the first time find that graphdiyne oxide (GDO) exhibits an ultrafast humidity response with an unprecedented response speed (~ 7 ms), which is considered to benefit from the unique carbon hybridization of GDO that contains acetylenic bonds with stronger electron-withdrawing property than ethylenic bonds in GO...
February 19, 2018: Angewandte Chemie
B Dumontel, M Canta, H Engelke, A Chiodoni, L Racca, A Ancona, T Limongi, G Canavese, V Cauda
The widespread use of ZnO nanomaterials for biomedical applications, including therapeutic drug delivery or stimuli-responsive activation, as well as imaging, imposes a careful control over the colloidal stability and long-term behaviour of ZnO in biological media. Moreover, the effect of ZnO nanostructures on living cells, in particular cancer cells, is still under debate. This paper discusses the role of surface chemistry and charge of zinc oxide nanocrystals, of around 15 nm in size, which influence their behaviour in biological fluids and effect on cancer cells...
November 28, 2017: Journal of Materials Chemistry. B, Materials for Biology and Medicine
Peter Bösiger, Isabelle M T Richard, Luce Le Gat, Benjamin Michen, Mark Schubert, René M Rossi, Giuseppino Fortunato
Chitosan is a promising biocompatible polymer for regenerative engineering applications, but its processing remains challenging due to limited solubility and rigid crystalline structure. This work represents the development of electrospun chitosan/poly(ethylene oxide) blend nanofibrous membranes by means of a numerical analysis in order to identify and tailor the main influencing parameters with respect to accessible surface nitrogen functionalities which are of importance for the biological activity as well as for further functionalization...
April 15, 2018: Carbohydrate Polymers
A Hassan, D I Pritchard, A M Ghaemmaghami
Despite the profound health implications of Necator americanus infection in humans, many aspects of its interaction with the host immune system are poorly understood. Here we investigated the early events at the interface of N. americanus larvae (L3) and human dendritic cells (DCs). Our data show that co-culturing DCs and the larvae trigger ex-sheathing of hookworms rapidly where a majority of DCs are sequestered onto the larval sheath allowing the ex-sheathed larvae to migrate away unchallenged. Intriguingly, DCs show negligible interaction with the ex-sheathed larvae, alluding to differences between the surface chemistry of the larva and its sheath...
February 19, 2018: Parasitology
Jiaqi Yu, Maria-Cristina Romeo, Alex A Cavallaro, Hak-Kim Chan
Amorphous powders are thermodynamically unstable, significantly impacting the processing, storage and performance of a product. Therefore, stabilization of the amorphous contents is in demand. In this study, disodium cromoglycate (DSCG) powder was chosen as a model drug because it is amorphous and highly hygroscopic after spray drying. Sodium stearate (NaSt) was co-spray dried with DSCG at various concentrations (10, 50 and 90% w/w) to investigate its effect against moisture-induced deterioration on the in vitro aerosolization performance of DSCG...
February 15, 2018: International Journal of Pharmaceutics
Koyeli Girigoswami
In the recent times, nanomaterials are used in many sectors of science, medicine and industry, without revealing its toxic effects. Thus, it is in urgent need for exploring the toxicity along with the application of such useful nanomaterials. Nanomaterials are categorized with a particle size of 1-100 nm. They have gained increasing attention because of their novel properties, including a large specific surface area and high reaction activity. The various fundamental and practical applications of nanomaterials include drug delivery, cell imaging, and cancer therapy...
2018: Advances in Experimental Medicine and Biology
Yubin Li, Dianwen Ju
In the past decades, nanoparticles have been widely used in industry and pharmaceutical fields for drug delivery, anti-pathogen, and diagnostic imaging purposes because of their unique physicochemical characteristics such as special ultrastructure, dispersity, and effective cellular uptake properties. But the nanotoxicity has been raised over the extensive applications of nanoparticles. Researchers have elucidated series of mechanisms in nanoparticles-induced toxicity, including apoptosis, necrosis, oxidative stress, and autophagy...
2018: Advances in Experimental Medicine and Biology
Anasua Mukhopadhayay, Tarasankar Das, Anindya Datta, Kamendra P Sharma
Solvents particularly those having low-volatility are of great interest for the biocatalytic synthesis of utility chemicals and fuels. Here we show novel and universal solvent-like properties of a neat and water-less polymer surfactant-BSA conjugated material (WL-PSpBSA). This highly viscous, non-volatile material, behaves as a liquid above its solid-liquid transition temperature (≈ 25-27 °C), and can be used as a solvent for variety of completely dry solutes of different sizes, and surface chemistries. We show using a combination of optical microscopy, steady state and time-resolved fluoresence spectroscopy, that dry and powdered dyes (hydrophobic Coumarin 153; C153), enzymes (α-chymotrypsin; α-Chy), or even 2 μm microparticles (diffusion coefficient ca...
February 16, 2018: Biomacromolecules
Florent Calvo, Ersin Yurtsever, Adem Tekin
The interaction between hydrogen and carbonaceous nanostructures is of fundamental interest in various areas of physical chemistry. In this contribution we have revisited the physisorption of hydrogen molecules and H2 clusters on fullerenes, following a first-principles approach in which the interaction is quantitatively evaluated for the C20 system using high-level electronic structure methods. Relative to coupled cluster data at the level of single, double, and perturbative triple excitations [CCSD(T)] taken as benchmark, the results for rotationally averaged physisorbed H2 show a good performance of MP2 variants and symmetry-adapted perturbation theory (SAPT), but significant deviations and basis set convergence issues are found for dispersion-corrected density functional theory (DFT)...
February 16, 2018: Journal of Physical Chemistry. A
Bo Wei, Michael Schroeder, Manfred Martin
The surface chemistry and the Cr tolerance ability of oxygen electrodes play a vital role in the performance and long-term stability of solid oxide cells (SOCs). In this paper, the surface cation segregations on the double perovskite oxide PrBaCo2O5+δ (PBCO) and its relationship with Cr deposition are reported. During high temperature annealing in an O2 atmosphere, the elements Ba and Co diffuse out of the lattice and form many BaO and Co3O4 precipitates on the surface, mainly located at grain boundaries. In the presence of volatile Cr species, the observation of BaCrO4 but not CoCr2O4 on a segregated PBCO surface reveals that the Cr deposition preferentially takes place on segregated BaO rather than on Co3O4 precipitates...
February 16, 2018: ACS Applied Materials & Interfaces
Weiyu Ning, Zhenghan Di, Yingjie Yu, Pingmei Zeng, Chunzhi Di, Daquan Chen, Xueqian Kong, Guangjun Nie, Yuliang Zhao, Lele Li
Surface functionality is an essential component for processing and application of metal-organic frameworks (MOFs). A simple and cost-effective strategy for DNA-mediated surface engineering of zirconium-based nanoscale MOFs (NMOFs) is presented, capable of endowing them with specific molecular recognition properties and thus expanding their potential for applications in nanotechnology and biotechnology. It is shown that efficient immobilization of functional DNA on NMOFs can be achieved via surface coordination chemistry...
February 16, 2018: Small
Hongxu Lu, Martina H Stenzel
Multicellular tumor spheroid models (MCTS) are often coined as 3D in vitro models that can mimic the microenvironment of tissues. MCTS have gained increasing interest in the nano-biotechnology field as they can provide easily accessible information on the performance of nanoparticles without using animal models. Considering that many countries have put restrictions on animals testing, which will only tighten in the future as seen by the recent developments in the Netherlands, 3D models will become an even more valuable tool...
February 16, 2018: Small
Fuyuan Zhang, Bing Liu, Guozhen Liu, Yan Zhang, Junping Wang, Shuo Wang
Based on the structural features of fluometuron, an immunizing hapten was synthesized and conjugated to bovine serum albumin as an immunogen to prepare a polyclonal antibody. However, the resultant antibody indicated cross-reactivity with 6 structurally similar phenylurea herbicides, with binding activities (expressed by IC 50 values) ranging from 1.67 µg/L to 42.71 µg/L. All 6 phenylurea herbicides contain a common moiety and three different substitutes. To understand how these three different chemical groups affect the antibody-phenylurea recognition activity, quantum chemistry, using density function theory (DFT) at the B3LYP/6-311++ G(d,p) level of theory, was employed to optimize all phenylurea structures, followed by determination of the 3D conformations of these molecules, pharmacophore analysis, and molecular electrostatic potential (ESP) analysis...
February 15, 2018: Scientific Reports
Zhenyuan Xia, Ryota Kabe, Andrea Liscio, Alessandro Kovtun, Emanuele Treossi, Xinliang Feng, Vincenzo Palermo
In this study we describe a simple and fast procedure for the covalent functionalization of pristine graphene with a pyrene-terminated alkylazide, transformed in a highly reactive radical by thermal activation. The functionalized graphene sheets showed enhanced dispersibility in organic solvents compared to the pristine ones, thus enhancing their solution processability and compatibility with solvents or polymers. The relative improvement of solubility estimated form the absorption spectra was ≈60% in CHCl3 and ≈1200% in THF...
February 1, 2018: Journal of Nanoscience and Nanotechnology
Madhab Bera, Pragya Gupta, Pradip K Maji
Facile one pot synthesis of graphene oxide (GO) by sonication assisted mechanochemical approach has been reported here. The amalgamation of ultrasonication and mechanical stirring has assisted the synthesis of GO in a short time duration of only 4 hours with good reaction yield. The structural characterization of GO was performed by X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), UV-Visible spectroscopy and Raman spectroscopy. Atomic force microscopic (AFM) analysis manifested the flake like morphology of GO with average sheet thickness ~1...
February 1, 2018: Journal of Nanoscience and Nanotechnology
Hua Zhang, Li Zhang, Zhaodong Li, Qionghua Wu, Jianli Gao
In this study, three commercially available nanodiamonds (NDs) of similar size (about 5 nm in diameter) but with different surface chemistry (-COOH, -NH2 and -poly(ethylene glycol)) were used to study the toxicity and immune activation of Raw264.7 cells. Only ND-PEG is well dispersed in water and cell culture medium (about 10 nm in diameter), while ND-COOH and ND-NH2 only showed some aggregation, about 50 nm in water and about 100 nm in cell culture medium. The three NDs showed different zeta potentials in water but the difference disappeared in cell culture medium due to the surface adsorption of the proteins...
February 1, 2018: Journal of Nanoscience and Nanotechnology
Wolfgang Tremel, Karsten Korschelt, Muhammad Nawaz Tahir
We describe elementary concepts, up-to-date developments, and per-spectives of the emerging field of nanoparticle enzyme mimics (so-called "nanozymes") at the interface of chemistry, biology, materials, and nanotechnology. The design and synthesis of functional enzyme mimics is a long-standing goal of biomimetic chemistry. Metal com-plexes, polymers and engineered biomolecules capturing the structure of natural enzymes or their active centers have been made to achieve high rates and enhanced selectivities...
February 15, 2018: Chemistry: a European Journal
Yu Tang, Lingjuan Ma, Jian Dou, Christopher M Andolina, Yuting Li, Hongbin Ma, Stephen D House, Xiaoyan Zhang, Judith Yang, Franklin Feng Tao
In situ/operando studies of a heterogeneous catalyst are particularly valuable for achieving a fundamental understanding of catalytic mechanisms at a molecular level by establishing a correlation between the observed catalytic performance and the corresponding surface chemistry during catalysis. Herein, CO oxidation on cobalt oxides was studied via ambient pressure X-ray photoelectron spectroscopy (AP-XPS). During CO oxidation on CoO in the temperature range of 140-180 °C, the active surface phase of CoO progressively transforms to Co 3 O 4 ...
February 15, 2018: Physical Chemistry Chemical Physics: PCCP
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