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nanomaterials, chemistry

Jonas G Croissant, Xavier Cattoën, Jean-Olivier Durand, Michel Wong Chi Man, Niveen M Khashab
Organic-inorganic hybrid materials garner properties from their organic and inorganic matrices as well as synergistic features, and therefore have recently attracted much attention at the nanoscale. Non-porous organosilica hybrid nanomaterials with a high organic content such as silsesquioxanes (R-SiO1.5, with R organic groups) and bridged silsesquioxanes (O1.5Si-R-SiO1.5) are especially attractive hybrids since they provide 20 to 80 weight percent of organic functional groups in addition to the known chemistry and stability of silica...
November 29, 2016: Nanoscale
Shaoheng Tang, Chuanqi Peng, Jing Xu, Bujie Du, Qingxiao Wang, Rodrigo D Vinluan, Mengxiao Yu, Moon J Kim, Jie Zheng
Identifying key factors that govern the in vivo behavior of nanomaterials is critical to the clinical translation of nanomedicines. Overshadowed by size-, shape-, and surface-chemistry effects, the impact of the particle core density on clearance and tumor targeting of inorganic nanoparticles (NPs) remains largely unknown. By utilizing a class of ultrasmall metal NPs with the same size and surface chemistry but different densities, we found that the renal-clearance efficiency exponentially increased in the early elimination phase while passive tumor targeting linearly decreased with a decrease in particle density...
November 24, 2016: Angewandte Chemie
Vlastimil Mazanek, Alena Libanska, Jiri Sturala, Daniel Bouša, David Sedmidubský, Martin Pumera, Zbynek Janousek, Jan Plutnar, Zdenek Sofer
Fluorographene is the youngest stoichiometric derivative of graphene, thus, its reactivity is just poorly explored. Compared to graphene, a significantly higher reactivity of C-F bonds makes this material a suitable platform for a large number of chemical modifications. Fluorographene is also the only member of halogengraphenes family, which can be prepared in stoichiometric composition C1F1. Here, we present the chemical modification of fluorographene with Grignard reagents which are well known in organic chemistry for the formation of new C-C bonds...
November 23, 2016: Chemistry: a European Journal
Marion Landry, Mathieu Pinault, Stéphane Tchankouo, Émeline Charon, Audrey Ridoux, Jorge Boczkowski, Martine Mayne-L'Hermite, Sophie Lanone
BACKGROUND: Carbon nanotubes (CNT) can interact with the biological environment, which could participate in their associated toxicity. We recently demonstrated that pH is an important player of CNT fate inside macrophages. We wanted to further characterize such process, and therefore designed a study dedicated to decipher CNT biodegradation by macrophages, as a function of two major physico-chemical properties in regard with nanotoxicology; length and degree of functionalization. To achieve our aim, we synthesized, following a single initial production process, four MWCNT differing in length and/or surface chemistry: S-CNT (short), SF-CNT (short functionalized), L-CNT (long) and LF-CNT (long functionalized)...
November 24, 2016: Particle and Fibre Toxicology
Francisco Morales-Lara, María Domingo-García, Rafael López-Garzón, María Luz Godino-Salido, Antonio Peñas-Sanjuán, F Javier López-Garzón, Manuel Pérez-Mendoza, Manuel Melguizo
Controlling the chemistry on the surface of new carbon materials is a key factor to widen the range of their applicability. In this paper we show a grafting methodology of polyalkylamines to the surface of carbon nanomaterials, in particular, carbon nanotubes and a carbon black. The aim of this work is to reach large degrees of covalent functionalization with hyperbranched polyethyleneimines (HBPEIs) and to efficiently preserve the strong chelating properties of the HBPEIs when they are fixed to the surface of these carbon materials...
2016: Science and Technology of Advanced Materials
Dengjun Wang, Chongyang Shen, Yan Jin, Chunming Su, Lingyang Chu, Dongmei Zhou
Understanding the fate and transport including remobilization of graphene oxide nanomaterials (GONMs) in the subsurface would enable us to expedite their benign use and evaluate their environmental impacts and health risks. In this study, the retention and release of GONMs were investigated in water-saturated columns packed with uncoated sand (Un-S) or iron oxide-coated sand (FeS) at environmentally relevant solution chemistries (1-100mM KCl and 0.1-10mM CaCl2 at pH7 and 11). Our results showed that increasing ionic strength (IS) inhibited GONMs' transport, and the impact of K(+) was less than Ca(2+)...
November 17, 2016: Science of the Total Environment
Stefan Wuttke, Andreas Zimpel, Thomas Bein, Simone Braig, Katharina Stoiber, Angelika Vollmar, Dominik Müller, Kirsten Haastert-Talini, Jörn Schaeske, Meike Stiesch, Gesa Zahn, Alexander Mohmeyer, Peter Behrens, Oliver Eickelberg, Deniz A Bölükbas, Silke Meiners
Metal-organic frameworks (MOFs) are promising platforms for the synthesis of nanoparticles for diverse medical applications. Their fundamental design principles allow for significant control of the framework architecture and pore chemistry, enabling directed functionalization for nanomedical applications. However, before applying novel nanomaterials to patients, it is imperative to understand their potential health risks. In this study, the nanosafety of different MOF nanoparticles is analyzed comprehensively for diverse medical applications...
November 15, 2016: Advanced Healthcare Materials
Katia Martina, Silvia Tagliapietra, Alessandro Barge, Giancarlo Cravotto
The combination of microwave heating and ultrasound irradiation has been successfully exploited in applied chemistry. Besides saving energy, these green techniques promote faster and more selective transformations. The aim of this review is to provide a practical overview of the complimentary and synergistic effects generated by the combination of microwaves and either ultrasound or hydrodynamic cavitation. This will begin with a brief history, as we outline pioneering achievements, and will also update the reader on recent developments...
December 2016: Topics in Current Chemistry (Journal)
Stephen Schrettl, Bjoern Schulte, Holger Frauenrath
Carbon-based materials show a remarkable variety of physical properties. For this reason, they have recently been explored for many advanced applications and emerging technologies. In the absence of actual "chemical" functionalities in these materials, tailoring these physical properties requires control on all levels of the structural hierarchy, from the atomic structure (carbon connectivity, defects, impurities), to the supramolecular level (domain orientations), nanoscopic length scale (domain sizes, porosity), microscopic structure (morphology), and macroscopic aspects (shape, surface chemistry)...
December 7, 2016: Nanoscale
Kausar B Riaz Ahmed, Amber M Nagy, Ronald P Brown, Qin Zhang, Subhas G Malghan, Peter L Goering
Silver nanoparticles (AgNPs) have generated a great deal of interest in the research, consumer product, and medical product communities due to their antimicrobial and anti-biofouling properties. However, in addition to their antimicrobial action, concerns have been expressed about the potential adverse human health effects of AgNPs. In vitro cytotoxicity studies often are used to characterize the biological response to AgNPs and the results of these studies may be used to identify hazards associated with exposure to AgNPs...
November 3, 2016: Toxicology in Vitro: An International Journal Published in Association with BIBRA
Lin Duan, Rongjie Hao, Zhu Xu, Xizhen He, Adeyemi S Adeleye, Yao Li
With the increasing use of graphene oxide (GO) nanomaterials, its possible environmental release and human effects have received much attention. As GO may enter drinking or wastewater treatment systems like other carbonaceous nanomaterials, and have potential impact on human and/or environmental health, its removal efficiency during water treatment is important and requires investigation. In this study, the removal efficiency of GO during water treatment procedure via coagulation was evaluated, and the effects of solution chemistry and natural organic matter on the coagulation-based removal of GO nanomaterials were investigated...
November 2, 2016: Chemosphere
E Kuijpers, C Bekker, D Brouwer, M Le Feber, W Fransman
Exposure assessment for nano-objects, and their aggregates and agglomerates (NOAA) has evolved from explorative research towards more comprehensive exposure assessment, providing data to further develop currently used conservative control banding (CB) tools for risk assessment. This study aims to provide an overview of current knowledge on emission potential of NOAA across the occupational life cycle stages by a systematic review and subsequently use the results in a data analysis. Relevant parameters that influence emission were collected from peer-reviewed literature with a focus on the four source domains (SD) in the source-receptor conceptual framework for NOAA...
November 1, 2016: Journal of Occupational and Environmental Hygiene
Linnan Li, Wen Ma, Sensen Shen, Hexiang Huang, Yu Bai, Huwei Liu
A novel carboxyl-functionalized metal-organic framework for highly efficient uranium sorption was prepared through generic post-synthetic strategy, and this MOF's saturation sorption capacity is found to be as high as 314 mg·g-1. The preliminary application illustrated that the grafted free-standing carboxyl groups have notably enhanced the sorption of uranyl ions on MIL-101. In addition, we have performed molecular dynamics simulation combined with density functional theory calculations to investigate the molecular insights of uranyl ions binding on MOFs...
October 27, 2016: ACS Applied Materials & Interfaces
Svenja Winzen, James Ciro Schwabacher, Julius Mueller, Katharina Landfester, Kristin Mohr
Surfactants, even in miniscule amounts, are often used for the synthesis and especially the stabilization of nanomaterials, which is essential for in vivo applications. In this study, we show that the interaction between nanoparticles and proteins strongly depends on the type of stabilizing surfactants and their (small) concentration changes. The reaction between human serum albumin (HSA) and polystyrene nanoparticles (PS-NPs) stabilized by an ionic or nonionic surfactant - sodium dodecyl sulfate (SDS) or Lutensol AT50, respectively - was monitored using isothermal titration calorimetry (ITC)...
October 26, 2016: Biomacromolecules
Haiou Qu, Sean W Linder, Thilak K Mudalige
Capillary electrophoresis (CE) is considered as a versatile technique in the size-based separation and speciation of nanomaterials. The electrophoretic mobility is determined by charge and size of an analyte which are affected by the surface composition of nanomaterials. Size-dependent differential electrophoretic mobility is used as a mechanism for size-based separation of nanoparticles. Understanding the effect of surface chemistry on the electrophoretic mobility of nanomaterials in CE is critical in obtaining accurate results in retention-based size calculation...
October 25, 2016: Analytical and Bioanalytical Chemistry
Guankui Wang, Fangfang Chen, Nirmal K Banda, V Michael Holers, LinPing Wu, S Moein Moghimi, Dmitri Simberg
While having tremendous potential as therapeutic and imaging tools, the clinical use of engineered nanoparticles has been associated with serious safety concerns. Activation of the complement cascade and the release of proinflammatory factors C3a and C5a may contribute to infusion-related reactions, whereas opsonization with C3 fragments promotes rapid recognition and clearance of nanomaterials by mononuclear phagocytes. We used dextran-coated superparamagnetic iron oxide nanoparticles (SPIO), which are potent activators of the complement system, to study the role of nanoparticle surface chemistry in inciting complement in human serum...
2016: Frontiers in Immunology
Dawei Xu, Qian Ran, Yang Xiang, Jiang Linhai, Britannia M Smith, Fadi Bou-Abdallah, Reidar Lund, Zhongjun Li, He Dong
A significant challenge associated with systemic delivery of cationic antimicrobial peptides and polymers lies in their limited hemocompatibility toward vast numbers of circulating red blood cells (RBCs). Supramolecular assembly of cationic peptides and polymers can be an effective strategy to develop an array of antimicrobial nanomaterials with tunable material structures, stability and thus optimized bioactivity to overcome some of the existing challenges associated with conventional antimicrobials. In this work, we will demonstrate the supramolecular design of self-assembling antimicrobial nanofibers (SAANs) which have tunable supramolecular nanostructures, stability, internal molecular packing and surface chemistry through self-assembly of de novo designed cationic peptides and peptide-PEG conjuguates...
2016: RSC Advances
Yu-Huei Peng, Yi-Chun Tsai, Chia-En Hsiung, Yi-Hsuan Lin, Yang-Hsin Shih
Zinc oxide nanoparticles (ZnO NPs) are widely used nanomaterials and their environmental impacts have received increasing attention. The fate and toxicity of ZnO NPs in the environment are determined by their stability and dissolution. In this study, the influence of water chemistry on aggregation, sedimentation, and dissolution of ZnO NPs was investigated. The stabilized ZnO NPs aggregated and precipitated when the aqueous pH closed to their zero point of charge (pHzpc). Counter-ions neutralized the surface charge of NPs and promoted their destabilization...
October 15, 2016: Journal of Hazardous Materials
Meghan B Teunis, Katie N Lawrence, Poulami Dutta, Amanda P Siegel, Rajesh Sardar
Organic-inorganic hybrid perovskites, direct band-gap semiconductors, have shown tremendous promise for optoelectronic device fabrication. We report the first colloidal synthetic approach to prepare ultrasmall (∼1.5 nm diameter), white-light emitting, organic-inorganic hybrid perovskite nanoclusters. The nearly pure white-light emitting ultrasmall nanoclusters were obtained by selectively manipulating the surface chemistry (passivating ligands and surface trap-states) and controlled substitution of halide ions...
October 14, 2016: Nanoscale
Peiguang Hu, Limei Chen, Xiongwu Kang, Shaowei Chen
Noble metal nanoparticles represent a unique class of functional nanomaterials with physical and chemical properties that deviate markedly from those of their atomic and bulk forms. In order to stabilize the nanoparticles and further manipulate the materials properties, surface functionalization with organic molecules has been utilized as a powerful tool. Among those, mercapto derivatives have been used extensively as the ligands of choice for nanoparticle surface functionalization by taking advantage of the strong affinity of thiol moieties to transition metal surfaces forming (polar) metal-thiolate linkages...
October 3, 2016: Accounts of Chemical Research
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