Refine
Has Fulltext
- no (156)
Year of publication
- 2016 (156) (remove)
Document Type
- Article (156) (remove)
Is part of the Bibliography
- yes (156)
Keywords
- Ion mobility spectrometry (3)
- X-ray structure (3)
- biomaterials (3)
- crystallization (3)
- Density functional calculations (2)
- IR-MALDI (2)
- Janus emulsions (2)
- Kinetics (2)
- Laser (2)
- Microemulsions (2)
- NMR spectroscopy (2)
- Nanoparticles (2)
- Oligo(epsilon-caprolactone) (2)
- Palladium (2)
- Theoretical calculations (2)
- configuration (2)
- conformation (2)
- copper(II) (2)
- crystal structure (2)
- electron paramagnetic resonance (2)
- fluorescent probes (2)
- microwave irradiation (2)
- nanoparticles (2)
- tetrabromidocuprate(II) (2)
- 1,2-dithiosquarate (1)
- 1,2-dithiosquaratometalate (1)
- 1D structures (1)
- 3-color fret (1)
- 3D structure (1)
- 4D NOESY (1)
- 8-oxohobartine (1)
- Absorptionsspektren (1)
- Adsorption (1)
- Adsorption of uremic toxins (1)
- AgAu alloy nanoparticles (1)
- Alkenes (1)
- Amides (1)
- Amines (1)
- Amino acids (1)
- Anisotropic gold nanoplatelets (1)
- Anserine (1)
- Aristotelia chilensis (1)
- Au nanoarrays (1)
- BBTP (1)
- Benzazepine (1)
- Biaryls (1)
- Bioelectrocatalysis (1)
- Biomass (1)
- Biomaterial (1)
- Biopolymers (1)
- Block copolymers (1)
- Bound states (1)
- Bragg coherent x-ray diffractive imaging (1)
- C-C coupling (1)
- CAL-72 osteoblasts (1)
- CC2 calculations (1)
- Calcium phosphates (1)
- Carbene ligands (1)
- Charge transfer (1)
- Chemical shift assignment (1)
- Chromophores (1)
- Chronic kidney disease (CKD) (1)
- Claisen rearrangement (1)
- Click chemistry (1)
- Collagen-binding peptide (1)
- Conformational analysis (1)
- Cross-coupling (1)
- Crystal packing (1)
- Crystal structure (1)
- DNA complexation (1)
- DNA origami (1)
- DNA origami nanostructures (1)
- DNA radiation damage (1)
- Decontamination (1)
- Depth profiling (1)
- Diastereoselectivity (1)
- Direct electron transfer (1)
- Discrete variable representation (1)
- Doping (1)
- Drop profile analysis tensiometry (1)
- Drug design (1)
- Dual scale factors (1)
- EPR spectroscopy (1)
- Electrochemistry (1)
- Electrospray ionization (1)
- Enantioselectivity (1)
- Energy transfer (1)
- Enzymatic degradation (1)
- Enzymatic polymer degradation (1)
- Equilibrium (1)
- Escherichia coli (1)
- External mass transfer (1)
- Extraction (1)
- FRET (1)
- FTO-Glas (1)
- FhuA (1)
- Fluorescence (1)
- Fluorescence spectroscopy (1)
- Fusarium proliferatum (1)
- Gelatin-chitosan composites (1)
- Gelatin-chitosan scaffolds (1)
- Generalized Langevin oscillator model (1)
- Grafting-from polymerization (1)
- HPLC (1)
- Heck reaction (1)
- High-harmonic generation (1)
- Homogeneous catalysis (1)
- Human sulfite oxidase (1)
- Hyaluronic acid (1)
- Hybrid materials (1)
- Hydrogels (1)
- Hydrogenation (1)
- Hydrophobin (1)
- Hypoosmotic stress (1)
- ICSS (1)
- IFT (1)
- Imaging (1)
- InP nanowires (1)
- Interfacial tension (1)
- Kinetic analysis (1)
- L-929 fibroblasts (1)
- LC composites (1)
- LCST (1)
- Lactams (1)
- Langmuir monolayer (1)
- Langmuir monolayer degradation technique (1)
- Langmuir technique (1)
- Laponite (1)
- Laser induced desorption (1)
- Leitendes Polymer (1)
- Light scattering (1)
- Liquid chromatography (1)
- Local density friction approximation (1)
- Maltose-modified poly(ethyleneimine) (1)
- Mass transfer (1)
- Matrix IR spectrum (1)
- Mechanical properties (1)
- Mesoporous materials (1)
- Modified Mannich reaction (1)
- Molecular dynamics simulations (1)
- Molecular dynamics with friction (1)
- Monolayer (1)
- Morphology (1)
- Multiblock copolymer (1)
- N ligands (1)
- NIPAAm (1)
- Na+ homeostasis (1)
- Nano-bioextractant (1)
- Nanocrystal growth (1)
- Nanotriangle stacking and welding (1)
- Nauclea diderrichii (1)
- Non-adiabatic transitions (1)
- Nuclear magnetic resonance (NMR) (1)
- Nucleophilic addition (1)
- Numerical propagation (1)
- Oligo(omega-pentadecalactone) (1)
- P ligands (1)
- Pendant drop tensiometry (1)
- Penicillium digitatum (1)
- Pesticides (1)
- Phase morphology (1)
- Pleurotus ostreatus (1)
- Poly-epsilon-caprolactone (1)
- Polyampholytes (1)
- Polyethyleneimine (1)
- Polymer architecture (1)
- Polyplexes (1)
- Porous scaffold (1)
- Porphyrins (1)
- Potentiostat (1)
- Protein (1)
- Protein voltammetry (1)
- Protein-polymer conjugate (1)
- Push-pull effect (1)
- Quantum dynamics (1)
- RAFT polymerization (1)
- Reactive foaming (1)
- Redoxreaktionen (1)
- Reduction (1)
- Respiration (1)
- Rheology (1)
- Ring method (1)
- Rotational barriers (1)
- Ruthenium (1)
- SANS (1)
- SAXS (1)
- SDS inverse micelle (1)
- SQM-FF (1)
- Schrodinger equation (1)
- Selenium (1)
- Self-assembly (1)
- Shadowgraphy (1)
- Silanes (1)
- Sodium transport (1)
- Spectroscopy (1)
- Spiro compounds (1)
- Staphylococcus aureus (1)
- Stereochemistry (1)
- Strontium (1)
- Structure elucidation (1)
- Sulfonamides (1)
- Surface chemistry (1)
- Surface removal (1)
- Synchrotron radiation XPS (1)
- Synthesis and processing (1)
- Synthetic methods (1)
- TSNMRS (1)
- Tautomerism (1)
- Temperature-memory effect (1)
- Tetrapyrroles (1)
- Thermomechanical history (1)
- Thermosensitivity (1)
- Thienopyridine (1)
- Transmembrane protein (1)
- Tubular network structure (1)
- Twisted double bonds (1)
- Two-dimensional separations (1)
- Vibrio cholerae (1)
- WAXS (1)
- Water (1)
- X-ray (1)
- X-ray scattering (1)
- Y-aromaticity (1)
- ab initio calculations (1)
- acids (1)
- activated urethane derivatives (1)
- actuation (1)
- adsorption (1)
- adsorption kinetics (1)
- aldehydes (1)
- alkyl nitrates (1)
- allyl alcohols (1)
- arenes (1)
- arsenious acid (1)
- assemblies (1)
- atomic force microscopy (1)
- atomic force microscopy (AFM) (1)
- azobenzene (1)
- bending stiffness (1)
- bio-inspired (1)
- biodegradable polymers (1)
- biodiversity (1)
- biomineralization (1)
- block copolymers (1)
- bone tissue engineering (1)
- bottom-up (1)
- cadmium (1)
- carbohydrate derivatives (1)
- carbohydrate derivatives (1)
- carboxyanhydrides (1)
- cardiovascular disease (1)
- cardiovascular implant (1)
- cellular uptake (1)
- chain mobility (1)
- cholesteric phase (1)
- chromenes (1)
- chromophores (1)
- chronic kidney disease (CKD) (1)
- click triazoles (1)
- colloidal aggregation (1)
- common species (1)
- cononsolvency (1)
- copolymers (1)
- coumarins (1)
- crown compounds (1)
- crystal structures (1)
- cyclooligomers (1)
- cytotoxicity (1)
- density functional calculations (1)
- dienes (1)
- differential scanning calorimetry (DSC) (1)
- dissociative electron attachment (1)
- drug carrier system (1)
- ecosystem function (1)
- effect of alkyl side chains (1)
- electrospinning (1)
- electrostatics (1)
- elektrochemische Abscheidung (1)
- elektrochemische Zelle (1)
- elektrochrome Schicht (1)
- elimination (1)
- ellipsometric mapping (1)
- enzyme catalysis (1)
- explosives (1)
- fludarabine (1)
- fluorescence (1)
- fluorescence anisotropy (1)
- fluorescence correlation spectroscopy (1)
- fluorescent dyemonomers (1)
- fronts (1)
- g-quadruplex (1)
- gas permeation (1)
- glass transition temperature (1)
- graphene (1)
- hemocompatibility (1)
- hole array (1)
- human monocytic (THP-1) cells (1)
- hydrogel (1)
- hydrophobic uremic toxins (1)
- identity hypothesis (1)
- impedance spectroscopy (1)
- in situ fluorescence microscopy (1)
- indole alkaloids (1)
- interaction potential (1)
- intracellular pH indicator (1)
- inverse micelles (1)
- ion mobility spectrometry (1)
- ionic liquids (1)
- ketones (1)
- land use (1)
- linear assemblies (1)
- liquid crystal (1)
- liquid crystal polymer (1)
- liquid crystalline polymer (1)
- lithography (1)
- lower critical solution temperature (1)
- luminescence (1)
- macrocyclic compounds (1)
- mass spectrometry (1)
- medicinal mushrooms (1)
- melt (1)
- melt-recrystallization (1)
- metal-organic frameworks (1)
- microgel (1)
- microgels (1)
- microparticles (1)
- molecular thermometers (1)
- mu CT imaging (1)
- multiblock copolymer (1)
- multiphoton processes (1)
- multitrophic (1)
- nanoimprint (1)
- nanoreactor (1)
- nanostructures (1)
- naphthalimide (1)
- olefination (1)
- organic-inorganic composite material (1)
- pH-sensitive liposome (1)
- paper (1)
- phenols (1)
- phosgene-free synthesis (1)
- photofragmentation (1)
- photoionization (1)
- photonic wires (1)
- photophysics (1)
- phototunable optical properties (1)
- pi-Electron delocalization (1)
- platelet activation (1)
- platelet adhesion (1)
- platelets (1)
- poly(2-ethyl-2oxazoline) (1)
- poly(N-vinylcaprolactam) (1)
- poly(dimethylsiloxane) (1)
- poly(ether imide) (1)
- poly(ether imide) microparticles (1)
- poly(ethylene glycol) (1)
- polyester (1)
- polymer crystallization (1)
- polymer solutions (1)
- polymeric sensors (1)
- polypeptides (1)
- polypeptoids (1)
- polystyrene-block-poly(4-vinylpyridine) (1)
- potassium (1)
- protecting groups (1)
- protein adsorption (1)
- quantum dots (1)
- reactive oxygen species (ROS) (1)
- recognition (1)
- recombinant protein (1)
- regioselectivity (1)
- resonance energy-transfer (1)
- ring closing metathesis (1)
- ring-opening polymerization (1)
- root mean square roughness (1)
- rotational diffusion (1)
- ruthenium (1)
- scale (1)
- scanning tunneling microscopy (1)
- selective drug release (1)
- selective light reflection (1)
- self-assembled micelles (1)
- self-assembled monolayers (1)
- self-organization (1)
- sensitivity (1)
- sensor (1)
- shape analysis (1)
- shape-memory effect (1)
- shape-persistent macrocycles (1)
- sodium (1)
- soft-templating (1)
- solvatochromism (1)
- spectroscopic ellipsometry (1)
- spider silk (1)
- steric hindrance (1)
- stimuli-sensitive polymers (1)
- strain field (1)
- strand breakage (1)
- strong field (1)
- substituent effects (1)
- surface plasmon resonance (1)
- systems (1)
- tandem reaction (1)
- temperature (1)
- thermo-responsive polymers (1)
- thermoresponsive (1)
- thermoresponsive polymers (1)
- thin films (1)
- thiophenes (1)
- thrombogenicity (1)
- time-dependent configuration interaction (1)
- time-resolved fluorescence spectroscopy (1)
- tin-rich ITO (1)
- translational diffusion (1)
- uremia (1)
- xanthenes (1)
- ylides (1)
- yolk@shell materials (1)
Institute
- Institut für Chemie (156) (remove)
BACKGROUND: Thrombogenicity is one of the main parameters tested in vitro to evaluate the hemocompatibility of artificial surfaces. While the influence of the temperature on platelet aggregation has been addressed by several studies, the temperature influence on the adherence of platelets to body foreign surfaces as an important aspect of biomedical device handling has not yet been explored. Therefore, we analyzed the influence of two typically applied incubation-temperatures (22 degrees C and 37 degrees C) on the adhesion of platelets to biomaterials. MATERIAL AND METHODS: Thrombogenicity of three different polymers - medical grade poly(dimethyl siloxane) (PDMS), polytetrafluoroethylene (PTFE) and polyethylene terephthalate (PET) - were studied in an in vitro static test. Platelet adhesion was studied with stringently characterized blood from apparently healthy subjects. Collection of whole blood and preparation of platelet rich plasma (PRP) was carried out at room temperature (22 degrees C). PRP was incubated with the polymers either at 22 degrees C or 37 degrees C. Surface adherent platelets were fixed, fluorescently labelled and assessed by an image-based approach. RESULTS AND DISCUSSION: Differences in the density of adherent platelets after incubation at 22 degrees C and 37 degrees C occurred on PDMS and PET. Similar levels of adherent platelets were observed on the very thrombogenic PTFE. The covered surface areas per single platelet were analyzed to measure the state of platelet activation and revealed no differences between the two incubation temperatures for any of the analyzed polymers. Irrespective of the observed differences between the low and medium thrombogenic PDMS and PET and the higher variability at 22 degrees C, the thrombogenicity of the three investigated polymers was evaluated being comparable at both incubation temperatures.
On the basis of the clinical studies in patients with coronary artery disease (CAD) presenting an increased percentage of activated platelets, we hypothesized that hemocompatibility testing utilizing platelets from healthy individuals may result in an underestimation of the materials' thrombogenicity. Therefore, we investigated the interaction of polymer-based biomaterials with platelets from CAD patients in comparison to platelets from apparently healthy individuals. In vitro static thrombogenicity tests revealed that adherent platelet densities and total platelet covered areas were significantly increased for the low (polydimethylsiloxane, PDMS) and medium (Collagen) thrombogenic surfaces in the CAD group compared to the healthy subjects group. The area per single platelet—indicating the spreading and activation of the platelets—was markedly increased on PDMS treated with PRP from CAD subjects. This could not be observed for collagen or polytetrafluoroethylene (PTFE). For the latter material, platelet adhesion and surface coverage did not differ between the two groups. Irrespective of the substrate, the variability of these parameters was increased for CAD patients compared to healthy subjects. This indicates a higher reactivity of platelets from CAD patients compared to the healthy individuals. Our results revealed, for the first time, that utilizing platelets from apparently healthy donors bears the risk of underestimating the thrombogenicity of polymer-based biomaterials.
The first heterodinuclear ruthenium(II) complexes of the 1,6,7,12-tetraazaperylene (tape) bridging ligand with iron(II), cobalt(II), and nickel(II) were synthesized and characterized. The metal coordination sphere in this complexes is filled by the tetradentate N,N-dimethyl-2,11-diaza[3.3](2,6)-pyridinophane (L-N4Me2) ligand, yielding complexes of the general formula [(L-N4Me2)Ru(mu-tape)M(L-N4Me2)](ClO4)(2)(PF6)(2) with M = Fe {[2](ClO4)(2)(PF6)(2)}, Co {[3](ClO4)(2)(PF6)(2)}, and Ni {[4](ClO4)(2)(PF6)(2)}. Furthermore, the heterodinuclear tape ruthenium(II) complexes with palladium(II)- and platinum(II)-dichloride [(bpy)(2)Ru(-tape)PdCl2](PF6)(2) {[5](PF6)(2)} and [(dmbpy)(2)Ru(-tape)PtCl2](PF6)(2) {[6](PF6)(2)}, respectively were also prepared. The molecular structures of the complex cations [2](4+) and [4](4+) were discussed on the basis of the X-ray structures of [2](ClO4)(4)MeCN and [4](ClO4)(4)MeCN. The electrochemical behavior and the UV/Vis absorption spectra of the heterodinuclear tape ruthenium(II) complexes were explored and compared with the data of the analogous mono- and homodinuclear ruthenium(II) complexes of the tape bridging ligand.
The research on protein-polymer conjugates by grafting from the surface of proteins has gained significant interest in the last decade. While there are many studies with globular proteins, membrane proteins have remained untouched to the best of our knowledge. In this study, we established the conjugate formation with a class of transmembrane proteins and grow polymer chains from the ferric hydroxamate uptake protein component A (FhuA; a beta-barrel transmembrane protein of Escherichia coli). As the lysine residues of naturally occurring FhuA are distributed over the whole protein, FhuA was reengineered to have up to 11 lysines, distributed symmetrically in a rim on the membrane exposed side (outside) of the protein channel and exclusively above the hydrophobic region. Reengineering of FhuA ensures a polymer growth only on the outside of the beta-barrel and prevents blockage of the channel as a result of the polymerization. A water-soluble initiator for controlled radical polymerization (CRP) was consecutively linked to the lysine residues of FhuA and N-isopropylacrylamide (NIPAAm) polymerized under copper mediated CRP conditions. The conjugate formation was analyzed by using MALDI-ToF mass spectrometry, SDS-PAGE, circular dichroism spectroscopy, analytical ultracentrifugation, dynamic light scattering, transmission electron microscopy and size exclusion chromatography. Such conjugates combine the specific functions of the transmembrane proteins, like maintaining membrane potential gradients or translocation of substrates with the unique properties of synthetic polymers such as temperature and pH stimuli handles. FhuA-PNIPAAm conjugates will serve as functional nanosized building blocks for applications in targeted drug delivery, self-assembly systems, functional membranes and transmembrane protein gated nanoreactors. (C) 2016 Elsevier Ltd. All rights reserved.
Responsive inverse opal hydrogels functionalized by boroxole moieties were synthesized and explored as sensor platforms for various low molar mass as well as polymeric diols and polyols, including saccharides, glycopolymers and catechols, by exploiting the diol induced modulation of their structural color. The underlying thermoresponsive water-soluble copolymers and hydrogels exhibit a coil-to-globule or volume phase transition, respectively, of the LCST-type. They were prepared from oligoethylene oxide methacrylate (macro)monomers and functionalized via copolymerization to bear benzoboroxole moieties. The resulting copolymers represent weak polyacids, which can bind specifically to diols within an appropriate pH window. Due to the resulting modulation of the overall hydrophilicity of the systems and the consequent shift of their phase transition temperature, the usefulness of such systems for indicating the presence of catechols, saccharides, and glycopolymers was studied, exploiting the diol/polyol induced shifts of the soluble polymers’ cloud point, or the induced changes of the hydrogels’ swelling. In particular, the increased acidity of benzoboroxoles compared to standard phenylboronic acids allowed performing the studies in PBS buffer (phosphate buffered saline) at the physiologically relevant pH of 7.4. The inverse opals constructed of these thermo- and analyte-responsive hydrogels enabled following the binding of specific diols by the induced shift of the optical stop band. Their highly porous structure enabled the facile and specific optical detection of not only low molar mass but also of high molar mass diol/polyol analytes such as glycopolymers. Accordingly, such thermoresponsive inverse opal systems functionalized with recognition units represent attractive and promising platforms for the facile sensing of even rather big analytes by simple optical means, or even by the bare eye.
Total protein concentration (TPC) is a key parameter in many biochemical experiments and its quantification is often necessary for isolation, separation, and analysis of proteins. A sensitive and rapid nanobead-based TPC quantification assay based on Forster Resonance Energy Transfer (FRET) has been developed. A new, highly luminescent Tb(III) complex has been synthesised and applied as donor in this FRET assay with an organic dye (Cy5) as acceptor. FRET-induced changes in luminescence have been investigated both at donor and acceptor emission wavelength using time-resolved luminescence spectroscopy with time-gated detection. In the assay, the Tb(III) complex and fine-tuned polyglycidyl methacrylate (PGMA) nanobeads ensure that an improvement in sensitivity and background reduction is achieved. Using 40 nm large PGMA nanobeads loaded with the Tb(III) complex, it is possible to determine TPC down to 50 ng mL(-1) in just 10 minutes. Through specific assay components the sensitivity has been improved when compared to existing nanobead-based assays and to currently known commercial methods. Additionally, the assay is relatively insensitive to the presence of contaminants, such as non-ionic detergents commonly found in biological samples. Due to no need for any centrifugal steps, this mix-and-measure bioassay can easily be implemented into routine TPC quantification protocols in biochemical laboratories.
Poly(2-alkyl-2-oxazoline)s (PAOx) exhibit different crystallization behavior depending on the length of the alkyl side chain. PAOx having methyl, ethyl, or propyl side chains do not show any bulk crystallization. Crystallization in the heating cycle, that is, cold crystallization, is observed for PAOx with butyl and pentyl side chains. For PAOx with longer alkyl side chains crystallization occurs in the cooling cycle. The different crystallization behavior is attributed to the different polymer chain mobility in line with the glass transition temperature (T-g) dependency on alkyl side chain length. The decrease in chain mobility with decreasing alkyl side chain length hinders the relaxation of the polymer backbone to the thermodynamic equilibrium crystalline structure. Double melting behavior is observed for PButOx and PiPropOx which is explained by the melt-recrystallization mechanism. Isothermal crystallization experiments of PButOx between 60 and 90 degrees C and PiPropOx between 90 and 150 degrees C show that PAOx can crystallize in bulk when enough time is given. The decrease of Tg and the corresponding increase in chain mobility at T > T-g with increasing alkyl side chain length can be attributed to an increasing distance between the polymer backbones and thus decreasing average strength of amide dipole interactions. (C) 2015 Wiley Periodicals, Inc.
Synchrotron-radiation XPS analysis of ultra-thin silane films: Specifying the organic silicon
(2016)
The analysis of chemical and elemental in-depth variations in ultra-thin organic layers with thicknesses below 5 nm is very challenging. Energy- and angle-resolved XPS (ER/AR-XPS) opens up the possibility for non-destructive chemical ultra-shallow depth profiling of the outermost surface layer of ultra-thin organic films due to its exceptional surface sensitivity. For common organic materials a reliable chemical in-depth analysis with a lower limit of the XPS information depth z(95) of about 1 nm can be performed. As a proof-of-principle example with relevance for industrial applications the ER/AR-XPS analysis of different organic monolayers made of amino- or benzamidosilane molecules on silicon oxide surfaces is presented. It is demonstrated how to use the Si 2p core-level region to non-destructively depth-profile the organic (silane monolayer) - inorganic (SiO2/Si) interface and how to quantify Si species, ranging from elemental silicon over native silicon oxide to the silane itself. The main advantage of the applied ER/AR-XPS method is the improved specification of organic from inorganic silicon components in Si 2p core-level spectra with exceptional low uncertainties compared to conventional laboratory XPS. (C) 2015 Elsevier B.V. All rights reserved.
Polysarcosine (M-n = 3650-20 000 g mol(-1), D similar to 1.1) was synthesized from the air and moisture stable N-phenoxycarbonyl-N-methylglycine. Polymerization was achieved by in situ transformation of the urethane precursor into the corresponding N-methylglycine-N-carboxyanhydride, when in the presence of a non-nucleophilic tertiary amine base and a primary amine initiator.
Polysarcosine (Mn = 3650–20 000 g mol−1, Đ ∼ 1.1) was synthesized from the air and moisture stable N-phenoxycarbonyl-N-methylglycine. Polymerization was achieved by in situ transformation of the urethane precursor into the corresponding N-methylglycine-N-carboxyanhydride, when in the presence of a non-nucleophilic tertiary amine base and a primary amine initiator.