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Surface Modification

Margherita Cacaci, Caroline Giraud, Loic Leger, Riccardo Torelli, Cecilia Martini, Brunella Posteraro, Valentina Palmieri, Maurizio Sanguinetti, Francesca Bugli, Axel Hartke
Enterococcus faecium is an important health care-associated pathogen that is difficult to treat due to the high level of antibiotic resistance of clinical isolates. The identification of new potential therapeutic targets or vaccination strategies is therefore urgently needed. In this regard, we carried out a transcriptomic analysis of the E. faecium vancomycin-resistant strain AUS0004, comparing the gene expression of bacteria grown under laboratory conditions and bacteria isolated from an infection site. This analysis highlighted more than 360 genes potentially induced under infection conditions...
August 17, 2018: Scientific Reports
Huanjiao Jenny Zhou, Zhe Xu, Zongren Wang, Haifeng Zhang, Michael Simons, Wang Min
Regulation of VEGFR2 represents an important mechanism for the control of angiogenesis. VEGFR2 activity can be regulated by post-translational modifications such as ubiquitination and acetylation. However, whether VEGFR2 can be regulated by SUMOylation has not been investigated. Here we show that endothelial-specific deletion of the SUMO endopeptidase SENP1 reduces pathological angiogenesis and tissue repair during hindlimb ischemia, and VEGF-induced angiogenesis in the cornea, retina, and ear. SENP1-deficient endothelial cells show increased SUMOylation of VEGFR2 and impaired VEGFR2 signalling...
August 17, 2018: Nature Communications
Zahra Amani-Beni, Alireza Nezamzadeh-Ejhieh
The sol-gel synthesized NiO nanoparticles were characterized and used for the modification of a carbon paste electrode (CPE) in electrocatalytic voltammetric determination of sulfasalazine. Calcination temperature of NiO had an important role on the peak current of the modified NiO-CPE and calcined NiO at 200 °C had the best and maximum peak current for the corresponding electrode. Jahn-Teller and a Z-out effects for the singlet electrons in their 3dz 2 orbital for calcined NiO at 200 °C relatively instable such electrons and hence they can easily participate in the electro-oxidation process...
November 15, 2018: Analytica Chimica Acta
Zheng Hao, Changhui Wang, Zaisheng Yan, Helong Jiang, Huacheng Xu
The separation and recovery of pollutant-loaded magnetic carbon materials from organic contaminated environment is recently concerned, but the change of sorption ability and mechanism of activated carbon and biochar caused by magnetic particles modification still need to be explored. Here, the magnetic modification of two coconut shell-, coal-derived activated carbon and one biochar, and its effect on the removal of phenol from water were investigated. Magnetic activated carbon (MAC) and magnetic biochar (MBC) were prepared by co-precipitation...
August 9, 2018: Chemosphere
Fengjie Deng, Huajian Zhou, Junyu Chen, Hongye Huang, Jianwen Tian, Yuanqing Wen, Qiang Huang, Meiying Liu, Xiaoyong Zhang, Yen Wei
Tb3+ -doped layered double hydroxides (LDHs) exhibit excellent optical characteristics, uniform size and uniform morphologies when synthesized through a hydrothermal method. However, due to their lack of functional groups and poor dispersibility, applications of these fluorescent Tb3+ -doped LDHs have been largely impeded especially in the biomedical fields. In this work, a novel strategy was developed for the surface modification of these fluorescent Tb3+ -doped LDHs using photoinduced surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization with hydrophilic poly(ethylene glycol) methacrylate (PEGMA) as the monomer...
August 10, 2018: Journal of Colloid and Interface Science
Xiangqian Li, Yuhui Zheng, Yiping Tang, Qi Chen, Jinwei Gao, Qi Luo, Qianming Wang
An efficient strategy for the synthesis of excitation-independent carbon nanodots has been provided. This functional nano-scale particle has been assembled by using citric acid and urea as raw materials through a microwave irradiation process in the absence of further surface modifications. The achieved nanomaterial demonstrates intensive green emissions and can be dispersible in aqueous environment. In particular, cerium (III) ion is able to quench its fluorescence emission intensity selectively and an "on-off" change has been observed...
August 13, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Jun Liu, Rujin Cheng, Haifan Wu, Shanshan Li, Peng G Wang, William F DeGrado, Sharon Rozovsky, Lei Wang
Analogous to reversible post-translational protein modifications, the ability to attach and subsequently remove modifications on proteins would be valuable for protein and biological research. Although bioorthogonal functionalities have been developed to conjugate or cleave protein modifications, they are introduced into proteins on separate residues and often with bulky side chains, limiting their use to one type of control and primarily protein surface. Here we achieved dual control on one residue by genetically encoding S-propargyl-cysteine (SprC), which has bioorthogonal alkyne and propargyl groups in a compact structure, permitting usage in protein interior in addition to surface...
August 17, 2018: Angewandte Chemie
Paula García Calavia, Gordon Bruce, Lluïsa Pérez-García, David A Russell
Gold nanoparticles (AuNPs) have been extensively studied within biomedicine due to their biocompatibility and low toxicity. In particular, AuNPs have been widely used to deliver photosensitiser agents for photodynamic therapy (PDT) of cancer. Here we review the state-of-the-art for the functionalisation of the gold nanoparticle surface with both photosensitisers and targeting ligands for the active targeting of cancer cell surface receptors. From the initial use of the AuNPs as a simple carrier of the photosensitiser for PDT, the field has significantly advanced to include: the use of PEGylated modification to provide aqueous compatibility and stealth properties for in vivo use; gold metal-surface enhanced singlet oxygen generation; functionalisation of the AuNP surface with biological ligands to specifically target over-expressed receptors on the surface of cancer cells and; the creation of nanorods and nanostars to enable combined PDT and photothermal therapies...
August 17, 2018: Photochemical & Photobiological Sciences
Laila Damiati, Marcus G Eales, Angela H Nobbs, Bo Su, Penelope M Tsimbouri, Manuel Salmeron-Sanchez, Matthew J Dalby
Titanium (Ti) plays a predominant role as the material of choice in orthopaedic and dental implants. Despite the majority of Ti implants having long-term success, premature failure due to unsuccessful osseointegration leading to aseptic loosening is still too common. Recently, surface topography modification and biological/non-biological coatings have been integrated into orthopaedic/dental implants in order to mimic the surrounding biological environment as well as reduce the inflammation/infection that may occur...
January 2018: Journal of Tissue Engineering
Matthias Bros, Lutz Nuhn, Johanna Simon, Lorna Moll, Volker Mailänder, Katharina Landfester, Stephan Grabbe
Nanocarriers (NC) are very promising tools for cancer immunotherapy. Whereas conventional vaccines are based on the administration of an antigen and an adjuvant in an independent fashion, nanovaccines can facilitate cell-specific co-delivery of antigen and adjuvant. Furthermore, nanovaccines can be decorated on their surface with molecules that facilitate target-specific antigen delivery to certain antigen-presenting cell types or tumor cells. However, the target cell-specific uptake of nanovaccines is highly dependent on the modifications of the nanocarrier itself...
2018: Frontiers in Immunology
Gopinath Kasetty, Praveen Papareddy, Ravi K V Bhongir, Mohamad N Ali, Michiko Mori, Malgorzata Wygrecka, Jonas S Erjefält, Anna Hultgårdh-Nilsson, Lena Palmberg, Heiko Herwald, Arne Egesten
Extracellular histones are present in the airways because of cell death occurring during inflammation. They promote inflammation and cause tissue damage due to their cationic nature. The anionic phosphoglycoprotein osteopontin (OPN) is expressed at high levels during airway inflammation and has been ascribed both pro- and anti-inflammatory roles. In this study, it was hypothesized that OPN may neutralize the harmful activities of extracellular histones at the airway mucosal surface. In a model of histone-induced acute lung injury, OPN-/- mice showed increased inflammation and tissue injury, and succumbed within 24 h, whereas wild-type mice showed lower degrees of inflammation and no mortality...
August 16, 2018: Mucosal Immunology
Andrius Dzedzickis, Vytautas Bucinskas, Darius Viržonis, Nikolaj Sesok, Arturas Ulcinas, Igor Iljin, Ernestas Sutinys, Sigitas Petkevicius, Justinas Gargasas, Inga Morkvenaite-Vilkonciene
Increasing the imaging rate of atomic force microscopy (AFM) without impairing of the imaging quality is a challenging task, since the increase in the scanning speed leads to a number of artifacts related to the limited mechanical bandwidth of the AFM components. One of these artifacts is the loss of contact between the probe tip and the sample. We propose to apply an additional nonlinear force on the upper surface of a cantilever, which will help to keep the tip and surface in contact. In practice, this force can be produced by the precisely regulated airflow...
August 16, 2018: Sensors
Tomi Mantel, Paul Benne, Stanislav Parsin, Mathias Ernst
Next to the pore size distribution, surface charge is considered to be one main factor in the separation performance of ultrafiltration (UF) membranes. By applying an external surface potential onto an electro-conductive UF membrane, electrostatic induced rejection was investigated. This study introduces in a first part a relatively simple but yet not reported technology of membrane modification with direct current sputter deposition of ultrathin (15 nm) highly conductive gold layers. In a second part, characterization of the gold-coated UF flat sheet membrane with a molecular weight cut-off (MWCO) of 150 kDa is presented...
August 16, 2018: Membranes
Zuzana Kolarova Raskova, Pavel Stahel, Jana Sedlarikova, Lenka Musilova, Monika Stupavska, Marian Lehocky
Stable antimicrobial nisin layers were prepared on the carrying medium-polyvinyl alcohol (PVA) films, crosslinked by glutaric acid. Surface plasma dielectric coplanar surface barrier discharge (DCSBD) modification of polyvinyl alcohol was used to improve the hydrophilic properties and to provide better adhesion of biologically active peptide-nisin to the polymer. The surface modification of films was studied in correlation to their cross-linking degree. Nisin was attached directly from the salt solution of the commercial product...
August 16, 2018: Materials
Eithne M Maguire, Stuart W A Pearce, Qingzhong Xiao
During atherosclerosis, the gradual accumulation of lipids into the subendothelial space of damaged arteries results in several lipid modification processes followed by macrophage uptake in the arterial wall. The way in which these modified lipoproteins are dealt with determines the likelihood of cholesterol accumulation within the monocyte-derived macrophage and thus its transformation into the foam cell that makes up the characteristic fatty streak observed in the early stages of atherosclerosis. The unique expression of chemokine receptors and cellular adhesion molecules expressed on the cell surface of monocytes points to a particular extravasation route that they can take to gain entry into atherosclerotic site, in order to undergo differentiation into the phagocytic macrophage...
August 13, 2018: Vascular Pharmacology
Aiguo Wang, Hua Song
Maximizing the production of aromatic hydrocarbons from lignin conversion by coupling methane activation without solvent was investigated over Zn-Ga modified zeolite catalyst. The co-loading of Zn and Ga greatly improves lignin conversion, arene yield along with BTEX (i.e., benzene, toluene, ethylbenzene, and xylene) selectivity, which gives 37.4 wt% yield of aromatic hydrocarbons with 62.2 wt% selectivity towards BTEX at 400 °C and 3.0 MPa. Methane presence has a negligible impact on lignin conversion, but improves arene yield and BTEX selectivity...
August 11, 2018: Bioresource Technology
Saumaya Kirti, Vinay M Bhandari, Jyotsnarani Jena, Arnab S Bhattacharyya
In the present study, two synthesis methods of nanocomposites-one involving a mixture of biomass and the other using chemical modification were investigated to evaluate practical application of green approach in pollution control, specifically for water and wastewater treatment. Newer multifunctional superparamagnetic nanocomposites using biomaterials such as unripened fruit of Cassia fistula (Golden shower) and Aloe vera were developed as an example of green approach while chemical modification was illustrated using n-octanol...
August 13, 2018: Journal of Environmental Management
Putao Zhang, Fu Yang, Muhammad Akmal Kamarudin, Chi Huey Ng, Gaurav Kapil, Tingli Ma, Shuzi Hayase
TiO2 is commonly used as electron transporting materials in perovskite photovoltaic devices due to its advantages, including suitable band gap, good photoelectrochemical stability and simple preparation process. However, there are many oxygen vacancies or defects on the surface of TiO2 and thus this affect the stability of TiO2 based perovskite solar cells under UV light. In this work, a thin (monolayer) SbI3 modification layer is introduced on mesoporous TiO2 surface and the effect at the interface between of TiO2 and perovskite is monitored by using quartz crystal microbalance system...
August 16, 2018: ACS Applied Materials & Interfaces
Goutam Ghosh, Sarah J Belh, Callistus Chiemezie, Niluksha Walalawela, Ashwini A Ghogare, Mariana Vignoni, Andrés H Thomas, Sherri A McFarland, Edyta M Greer, Alexander Greer
There is a major need for light-activated materials for the release of sensitizers and drugs. Considering the success of chiral columns for the separation of enantiomer drugs, we synthesized an S,S-chiral linker system covalently attached to silica with a sensitizer ethene near the silica surface. First, the silica surface was modified to be aromatic rich, by replacing 70% of the surface groups with (3-phenoxypropyl)silane. We then synthesized a 3-component conjugate [chlorin sensitizer, S,S-chiral cyclohexane, and ethene building blocks] in 5 steps with a 13% yield, and covalently bound the conjugate to the (3-phenoxypropyl)silane-coated silica surface...
August 16, 2018: Photochemistry and Photobiology
Liping Mei, Mingliang Jin, Shuting Xie, Zhibin Yan, Xin Wang, Guofu Zhou, Albert van den Berg, Lingling Shui
We report an easily-established capillary-based open microfluidic device (COMD) as a simple and robust method for size on-demand generation of monodisperse droplets of various fluidic materials with controllable volume. A device is set up in which a capillary is positioned with its tip close to a flat surface with a precise gap distance in a container. The continuous phase remains static in the container, and the dispersed phase is pumped through the capillary and forms droplets at the exit of the gap. Monodisperse droplets, bubbles and microcapsules of various fluids with diameters of 10-300 μm (picoliter to nanoliter) and generation frequency of 1-1000 Hz are obtained by controlling the gap distance in the range of 5-500 μm...
August 16, 2018: Lab on a Chip
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