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Surface chemistry

Ting Wei, Wenjun Zhan, Limin Cao, Changming Hu, Yangcui Qu, Qian Yu, Hong Chen
Development of a versatile strategy for antibacterial surfaces is of great scientific interest and practical significance. However, few methods can be used to fabricate antibacterial surfaces on substrates of different chemistries and structures. In addition, traditional antibacterial surfaces may suffer problems related to the attached dead bacteria. Herein, antibacterial surfaces with multifunctionality and regenerability are fabricated by a universal strategy. Various substrates are firstly deposited with multilayered films containing guest moieties, which further serve as binding sites for incorporation of biocidal "host" molecules, β-cyclodextrin (β-CD) derivatives modified with quaternary ammonium salt groups (CD-QAS)...
October 19, 2016: ACS Applied Materials & Interfaces
Nathaniel Charles Wardrip, Melissa Dsouza, Meltem Urgun-Demirtas, Seth W Snyder, Jack A Gilbert, Christopher J Arnusch
Understanding and restricting microbial surface attachment will enhance wastewater treatment with membranes. We report a maskless lithographic patterning technique for the generation of patterned polymer coatings on ultrafiltration membranes. Polyethylene glycol, zwitterionic, or negatively charged hydrophilic polymer compositions in parallel- or perpendicular-striped patterns with respect to feed flow were evaluated using wastewater. Membrane fouling was dependent on the orientation and the chemical composition of the coatings...
October 17, 2016: ACS Applied Materials & Interfaces
Dogan Erbahar, Toma Susi, Xavier Rocquefelte, Carla Bittencourt, Mattia Scardamaglia, Peter Blaha, Peter Guttmann, Georgios Rotas, Nikos Tagmatarchis, Xiaohui Zhu, Adam P Hitchcock, Chris P Ewels
C60 fullerene crystals may serve as important catalysts for interstellar organic chemistry. To explore this possibility, the electronic structures of free-standing powders of C60 and (C59N)2 azafullerenes are characterized using X-ray microscopy with near-edge X-ray adsorption fine structure (NEXAFS) spectroscopy, closely coupled with density functional theory (DFT) calculations. This is supported with X-ray photoelectron spectroscopy (XPS) measurements and associated core-level shift DFT calculations. We compare the oxygen 1s spectra from oxygen impurities in C60 and C59N, and calculate a range of possible oxidized and hydroxylated structures and associated formation barriers...
October 17, 2016: Scientific Reports
Surender Kumar Sharawat, Vinod Raina, Lalit Kumar, Atul Sharma, Radhika Bakhshi, Sreenivas Vishnubhatla, Ritu Gupta, Sameer Bakhshi
BACKGROUND & OBJECTIVES: Mutations in fms-like tyrosine kinase 3 (FLT3) receptor have significant role in assessing outcome in patients with acute myeloid leukaemia (AML). Data for FLT3 surface expression in relation to FLT3 internal tandem duplication (ITD) status and outcome are not available from India. The objective of the current study was to investigate adult patients with AML for FLT3 expression and FLT3 ITD mutation, and their association with long-term outcome. METHODS: Total 51 consecutive de novo AML patients aged 18-60 yr were enrolled in the study...
May 2016: Indian Journal of Medical Research
Alberto Giacomello, Lothar Schimmele, Siegfried Dietrich, Mykola Tasinkevych
A liquid droplet placed on a geometrically textured surface may take on a "suspended" state, in which the liquid wets only the top of the surface structure, while the remaining geometrical features are occupied by vapor. This superhydrophobic Cassie-Baxter state is characterized by its composite interface which is intrinsically fragile and, if subjected to certain external perturbations, may collapse into the fully wet, so-called Wenzel state. Restoring the superhydrophobic Cassie-Baxter state requires a supply of free energy to the system in order to again nucleate the vapor...
October 17, 2016: Soft Matter
Adel Dalilottojari, Bahman Delalat, Frances J Harding, Michaelia P Cockshell, Claudine S Bonder, Nicolas H Voelcker
Porous silicon (pSi) substrates are a promising platform for cell expansion, since pore size and chemistry can be tuned to control cell behavior. In addition, a variety of bioactives can be loaded into the pores and subsequently released to act on cells adherent to the substrate. Here we construct a cell microarray on plasma polymer coated pSi substrates that enables the simultaneous culture of human endothelial cells on printed immobilized protein factors while a second soluble growth factor is released from the same substrate...
October 15, 2016: Biomacromolecules
Sarwar Beg, Mahfoozur Rahman, Atul Jain, Sumant Saini, Patrick Midoux, Chantal Pichon, Farhan Jalees Ahmad, Sohail Akhter
Metal organic frameworks (MOFs), porous hybrid polymer-metal composites at the nanoscale, are recent innovations in the field of chemistry; they are novel polymeric materials with diverse biomedical applications. MOFs are nanoporous materials, consisting of metal ions linked together by organic bridging ligands. The unique physical and chemical characteristics of MOFs have attracted wider attention from the scientific community, exploring their utility in the field of material science, biology, nanotechnology and drug delivery...
October 11, 2016: Drug Discovery Today
Erin Jo Tiedeken, Alexandre Tahar, Brendan McHugh, Neil J Rowan
Pollution of European receiving waters with contaminants of emerging concern (CECs), such as with 17-beta-estradiol (a natural estrogenic hormone, E2), along with pharmaceutically-active compounds diclofenac (an anti-inflammatory drug, DCL) and 17-alpha-ethynylestradiol (a synthetic estrogenic hormone, EE2)) is a ubiquitous phenomenon. These three CECs were added to the EU watch list of emerging substances to be monitoring in 2013, which was updated in 2015 to comprise 10 substances/groups of substances in the field of water policy...
October 11, 2016: Science of the Total Environment
Tanit Haddad, Samantha Noel, Benoît Liberelle, Rouwayda El Ayoubi, Abdellah Ajji, Gregory De Crescenzo
In an effort to design biomaterials that may promote repair of the central nervous system, 3-dimensional scaffolds made of electrospun poly lactic acid nanofibers with interconnected pores were fabricated. These scaffolds were functionalized with polyallylamine to introduce amine groups by wet chemistry. Experimental conditions of the amination protocol were thoroughly studied and selected to introduce a high amount of amine group while preserving the mechanical and structural properties of the scaffold. Subsequent covalent grafting of epidermal growth factor was then performed to further tailor these aminated structures...
October 14, 2016: Biomatter
Shalom D Goldberg, Rosa M F Cardoso, Tricia Lin, Tracy Spinka-Doms, Donna Klein, Steven A Jacobs, Vadim Dudkin, Gary Gilliland, Karyn T O'Neil
Targeted delivery of therapeutic payloads to specific tissues and cell types is an important component of modern pharmaceutical development. Antibodies or other scaffold proteins can provide the cellular address for delivering a covalently linked therapeutic via specific binding to cell-surface receptors. Optimization of the conjugation site on the targeting protein, linker chemistry and intracellular trafficking pathways can all influence the efficiency of delivery and potency of the drug candidate. In this study, we describe a comprehensive engineering experiment for an EGFR binding Centyrin, a highly stable fibronectin type III (FN3) domain, wherein all possible single-cysteine replacements were evaluated for expression, purification, conjugation efficiency, retention of target binding, biophysical properties and delivery of a cytotoxic small molecule payload...
October 13, 2016: Protein Engineering, Design & Selection: PEDS
Sameh K Elsaidi, Mona H Mohamed, John S Loring, Bernard Peter McGrail, Praveen K Thallapally
The synthetic approaches for fine-tuning the structural properties of coordination polymers or metal organic frameworks have exponentially grown during the last decade. This is due to the control over the properties of the resulting structures such as stability, pore size, pore chemistry and surface area for myriad possible applications. Herein, we present a new class of porous materials called Covalent Coordination Frameworks (CCFs) that were designed and effectively synthesized using a two-step reticular chemistry approach...
October 13, 2016: ACS Applied Materials & Interfaces
Jonathan Watté, Wouter Tony Mathias Van Gompel, Petra Leona Lommens, Klaartje De Buysser, Isabel Van Driessche
A method to obtain photocatalytically active thin films of anatase nanocrystals on polymer substrates was explored. Anatase nanocrystals were synthesized by a fast hydrolysis synthesis in an apolar solvent and characterized with regard to their crystallinity, size, dispersibility and stability of the resulting suspensions. The stable titania nanocrystal suspensions were further processed for their use in polar solvents using ligand exchange. Oleic acid was exchanged for 3-aminopropyltriethoxysilane (APTES), resulting in aqueous suspensions of charge-stabilized nanocrystals...
October 13, 2016: ACS Applied Materials & Interfaces
Izaskun Jiménez-Serra, Anton I Vasyunin, Paola Caselli, Nuria Marcelino, Nicolas Billot, Serena Viti, Leonardo Testi, Charlotte Vastel, Bertrand Lefloch, Rafael Bachiller
The detection of complex organic molecules (COMs) toward cold sources such as pre-stellar cores (with T<10 K), has challenged our understanding of the formation processes of COMs in the interstellar medium. Recent modelling on COM chemistry at low temperatures has provided new insight into these processes predicting that COM formation depends strongly on parameters such as visual extinction and the level of CO freeze out. We report deep observations of COMs toward two positions in the L1544 pre-stellar core: the dense, highly-extinguished continuum peak with A V ≥30 mag within the inner 2700 au; and a low-density shell with average A V ~7...
October 10, 2016: Astrophysical Journal. Letters
Junsheng Li, Barbara Kwiatkowska, Hao Lu, Maren Voglstätter, Erika Ueda, Michael Grunze, Jonathan Sleeman, Pavel A Levkin, Irina Nazarenko
Malignant transformation is associated with enhancement of cell plasticity, which allows cancer cells to survive under different conditions by adapting to their microenvironment during growth and metastatic spread. Much effort has been devoted to understanding the molecular mechanisms of these processes. Although the importance of the extracellular matrix and of surface properties in these mechanisms is evident, the direct impact of distinct physical and chemical surfaces characteristics on cell fate remains unclear...
October 12, 2016: ACS Applied Materials & Interfaces
Xuelin Tian, Ville Jokinen, Juan Li, Jani Sainio, Robin H A Ras
Thermodynamically unusual surfaces that possess two contradictory wetting properties, i.e., underoil superhydrophobicity and underwater superoleophobicity, are prepared by the combination of re-entrant topography and delicately matched surface chemistry. The preparation of such extraordinary surfaces relies on two key design criteria and employs a metastable state effect in solid-oil-water systems.
October 12, 2016: Advanced Materials
Nolan B Skop, Frances Calderon, Cheul H Cho, Chirag D Gandhi, Steven W Levison
Tissue engineering using stem cells is widely used to repair damaged tissues in diverse biological systems; however, this approach has met with less success in regenerating the central nervous system (CNS). In this study we optimized and characterized the surface chemistry of chitosan-based scaffolds for CNS repair. To maintain radial glial cell (RGC) character of primitive neural precursors, fibronectin was adsorbed to chitosan. The chitosan was further modified by covalently linking heparin using genipin, which then served as a linker to immobilize fibroblast growth factor-2 (FGF-2), creating a multifunctional film...
October 2016: Journal of Tissue Engineering and Regenerative Medicine
Zhaoyang Lin, Anxiang Yin, Jun Mao, Yi Xia, Nicholas Kempf, Qiyuan He, Yiliu Wang, Chih-Yen Chen, Yanliang Zhang, Vidvuds Ozolins, Zhifeng Ren, Yu Huang, Xiangfeng Duan
Epitaxial heterostructures with precisely controlled composition and electronic modulation are of central importance for electronics, optoelectronics, thermoelectrics, and catalysis. In general, epitaxial material growth requires identical or nearly identical crystal structures with small misfit in lattice symmetry and parameters and is typically achieved by vapor-phase depositions in vacuum. We report a scalable solution-phase growth of symmetry-mismatched PbSe/Bi2Se3 epitaxial heterostructures by using two-dimensional (2D) Bi2Se3 nanoplates as soft templates...
October 2016: Science Advances
Sitara Chauhan, Steven Danielson, Virginia Clements, Nathan J Edwards, Suzanne Ostrand-Rosenberg, Catherine Fenselau
In this report we use a proteomic strategy to identify glycoproteins on the surface of exosomes derived from myeloid-derived suppressor cells (MDSC), and then test if selected glycoproteins contribute to exosome-mediated chemotaxis and migration of MDSC. We report successful modification of a surface chemistry method for use with exosomes, and identify twenty-one surface N-glycoproteins on exosomes released by mouse mammary carcinoma-induced MDSC. These glycoprotein identities and functionalities are compared with ninty-three N-linked glycoproteins identified on the surface of the parental cells...
October 11, 2016: Journal of Proteome Research
Anton V Ievlev, Petro Maksymovych, Morgan Trassin, Jan Seidel, Ramamoorthy Ramesh, Sergei V Kalinin, Olga S Ovchinnikova
Domain formation and ferroelectric switching is fundamentally inseparable from polarization screening, which on free surfaces can be realized via band bending and ionic adsorption. In the latter case, polarization switching is intrinsically coupled to the surface electrochemical phenomena, and the electrochemical stage can control kinetics and induce long-range interactions. However, despite extensive evidence towards the critical role of surface electrochemistry, little is known about the nature of the associated processes...
October 11, 2016: ACS Applied Materials & Interfaces
H Van Bui, F Grillo, J R van Ommen
Atomic layer deposition (ALD) is a gas-phase deposition technique that, by relying on self-terminating surface chemistry, enables the control of the amount of deposited material down to the atomic level. While mostly used in semiconductor technology for the deposition of ceramic oxides and nitrides on wafers, ALD lends itself to the deposition of a wealth of materials on virtually every substrate. In particular, ALD and its organic counterpart molecular layer deposition (MLD), have opened up attractive avenues for the synthesis of novel nanostructured materials...
October 11, 2016: Chemical Communications: Chem Comm
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