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排序方式: 共有310条查询结果,搜索用时 31 毫秒
101.
Sumati Bhatia Malte Hilsch Jose Luis Cuellar‐Camacho Kai Ludwig Chuanxiong Nie Badri Parshad Matthias Wallert Stephan Block Daniel Lauster Christoph Bttcher Andreas Herrmann Rainer Haag 《Angewandte Chemie (International ed. in English)》2020,59(30):12417-12422
Flexible multivalent 3D nanosystems that can deform and adapt onto the virus surface via specific ligand–receptor multivalent interactions can efficiently block virus adhesion onto the cell. We here report on the synthesis of a 250 nm sized flexible sialylated nanogel that adapts onto the influenza A virus (IAV) surface via multivalent binding of its sialic acid (SA) residues with hemagglutinin spike proteins on the virus surface. We could demonstrate that the high flexibility of sialylated nanogel improves IAV inhibition by 400 times as compared to a rigid sialylated nanogel in the hemagglutination inhibition assay. The flexible sialylated nanogel efficiently inhibits the influenza A/X31 (H3N2) infection with IC50 values in low picomolar concentrations and also blocks the virus entry into MDCK‐II cells. 相似文献
102.
Tao Wei Malte Kohring Muqing Chen Shangfeng Yang Heiko B. Weber Frank Hauke Andreas Hirsch 《Angewandte Chemie (International ed. in English)》2020,59(14):5602-5606
Patterned graphene‐functionalization with a tunable degree of functionalization can tailor the properties of graphene. Here, we present a new reductive functionalization approach combined with lithography rendering patterned graphene‐functionalization easily accessible. Two types of covalent patterning of graphene were prepared and their structures were unambiguously characterized by statistical Raman spectroscopy together with scanning electron microscopy/energy‐dispersive X‐ray spectroscopy (SEM‐EDS). The reversible defunctionalization processes, as revealed by temperature‐dependent Raman spectroscopy, enable the possibility to accurately modulate the degree of functionalization by annealing. This allows for the management of chemical information through complete write/store/erase cycles. Based on our strategy, controllable and efficient patterning graphene‐functionalization is no longer a challenge and facilitates the development of graphene‐based devices. 相似文献
103.
Tandem Organocatalysis and Photocatalysis: An Anthraquinone‐Catalyzed Indole‐C3‐Alkylation/Photooxidation/1,2‐Shift Sequence
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Dipl.‐Chem. Stephanie Lerch B. Sc. Lisa‐Natascha Unkel Juniorprof. Dr. Malte Brasholz 《Angewandte Chemie (International ed. in English)》2014,53(25):6558-6562
Quinones exhibit orthogonal ground‐ and excited‐state reactivities and are therefore highly suitable organocatalysts for the development of sequential catalytic processes. Herein, the discovery of an anthraquinone‐catalyzed thermal indole‐C3‐alkylation with benzylamines is described, which can be combined sequentially with a new visible‐light‐driven catalytic photooxidation/1,2‐shift reaction. The one‐flask tandem process converts indoles into 3‐benzylindole intermediates, which are further transformed into new fluorescent 2,2‐disubstituted indoline‐3‐one derivatives. 相似文献
104.
Malte Grüner Vassilios Siozios Birgit Hagenhoff Daniel Breitenstein Cristian A. Strassert 《Photochemistry and photobiology》2013,89(6):1406-1412
In this work, we have quantified for the first time the fluorescence and singlet oxygen quantum yields of a silicon(IV) phthalocyanine bound to the surface of zeolite L nanocrystals. The photophysical properties were correlated with the absorption spectra and the morphology of the nanoparticles, and most importantly, with the fraction of photoactive chromophores. By comparison with the fluorescence and singlet oxygen quantum yields of the free phthalocyaninate in dilute solution (ΦF = 0.50 and Φ? = 0.50, respectively), we conclude that for the most efficient nanoparticles nearly 80% of chromophores are active as monomeric units on the surface, as indicated by the corresponding quantum yields (ΦF = 0.40 and Φ? = 0.40). We further functionalized and raised the ζ‐potential of the best performing nanomaterial to improve its water dispersibility. The functionalization was monitored by thermogravimetric analysis and time‐of‐flight secondary‐ion mass spectrometry, and its influence on the photophysical properties was assessed. The resulting nanomaterials are capable of establishing stable suspensions in water while retaining the ability to form reactive oxygen species upon irradiation with red light. This provides a basis for the rational design of photoactive nanomaterials for photodynamic therapy or water decontamination. 相似文献
105.
106.
Zhao C Zawisza I Nullmeier M Burchardt M Träuble M Witte I Wittstock G 《Langmuir : the ACS journal of surfaces and colloids》2008,24(14):7605-7613
Patterned cell cultures obtained by microcontact printing have been modified in situ by a microelectrochemical technique. It relies on lifting cell-repellent properties of oligo(ethylene glycol)-terminated self-assembled monolayers (SAMs) by Br2, which is produced locally by an ultramicroelectrode of a scanning electrochemical microscope (SECM). After Br2 treatment the SAM shows increased permeability and terminal hydrophobicity as characterized by SECM approach curves and contact angle measurements, respectively. Polarization-modulation Fourier transform infrared reflection-absorption spectroscopic (PM FTIRRAS) studies on macroscopic samples show that the Br2 treatment removes the oligo(ethelyene glycol) part of the monolayer within a second time scale while the alkyl part of the SAM degrades with a much slower rate. The lateral extension of the modification can be limited because heterogeneous electron transfer from the gold support destroys part of the electrogenerated Br2 once the monolayer is locally damaged in a SECM feedback configuration. This effect has been reproduced and analyzed by exposing SAM-modified samples to Br2 in the galvanic cell Au|SAM|5 microM Br2 + 0.1 M Na2SO4||10 microM KBr + 0.1 M Na2SO4|Au followed by an PM FTIRRAS characterization of the changes in the monolayer system. 相似文献
107.
Multilayer films of glucose oxidase (GOx) and poly(dimethyl diallyl ammonium chloride) (PDDA) prepared by layer-by-layer deposition were studied using scanning electrochemical microscopy (SECM). Aminated glass slides were coated with five bilayers of poly(styrene sulfonate) (PSS) and PDDA and used as substrates onto which GOx/PDDA multilayers were deposited. UV-Vis experiments confirmed multilayer growth, scanning force microscopic images provided morphological information about the films. SECM current-distance curves enabled the determination of kinetic information about GOx in GOx/PDDA multilayers as a function of layer number, film termination, inert covering layers, and enzyme substrate concentration after fitting to numerical models. The results indicate that only the topmost layers contributed significantly to the conversion. An odd-even pattern was observed for PDDA-terminated films or GOx-terminated films that correlated with morphological changes. 相似文献
108.
Dr. Brian P. Corbet J. Malte Schlüter Elena R. Cotroneo Dr. Stefano Crespi Prof. Dr. Nadja A. Simeth 《European journal of organic chemistry》2023,26(1):e202201140
Light-responsive molecules have seen a major advance in modulating biological functions in recent years. Especially photoswitches are highly attractive building blocks due to the reversible nature of their light-mediated reactivity. They are frequently used to affect both the properties of small bioactive compounds and biomacromolecules if incorporated suitably. Despite their success in a plethora of applications, only a limited set of photochromic core structures is routinely employed and a large number of photochromic couples are under-investigated in biological context. Broadening the toolbox of photoswitches available to modulate biological activity would open new avenues and unlock the full potential of photoswitchable molecules for biological studies. In this work, we explore the photochemical and thermal properties of the dihydroazulene/vinylheptafulvene photochromic couple as peptide conjugates in aqueous environment. 相似文献
109.
Susanne Weininger Malte Neudorf Stefan Gröger Eric Plato Robert Broneske Kay Saalwächter Ulrich Weininger Jochen Balbach 《Macromolecular bioscience》2023,23(5):2200526
In the human eye lenses, the crystallin proteins facilitate transparency, light refraction, as well as UV light protection. A deregulated balanced interplay between α-, β-, and γ-crystallin can cause cataract. γD-crystallin (hγD) is involved in the energy dissipation of absorbed UV light by energy transfer between aromatic side chains. Early UV-B induced damage of hγD with molecular resolution is studied by solution NMR and fluorescence spectroscopy. hγD modifications are restricted to Tyr 17 and Tyr 29 in the N-terminal domain, where a local unfolding of the hydrophobic core is observed. None of the tryptophan residues assisting fluorescence energy transfer is modified and hγD is remained soluble over month. Investigating isotope-labeled hγD surrounded by eye lens extracts from cataract patients reveals very week interactions of solvent-exposed side chains in the C-terminal hγD domain and some remaining photoprotective properties of the extracts. Hereditary E107A hγD found in the eye lens core of infants developing cataract shows under the here used conditions a thermodynamic stability comparable to the wild type but an increased sensitivity toward UV-B irradiation. 相似文献
110.
Dongyang Chen Francisco Tenopala-Carmona Julius A. Knöller Andreas Mischok David Hall Subeesh Madayanad Suresh Tomas Matulaitis Yoann Olivier Pierre Nacke Frank Gießelmann Sabine Laschat Malte C. Gather Eli Zysman-Colman 《Angewandte Chemie (International ed. in English)》2023,62(16):e202218911
The use of thermally activated delayed fluorescence (TADF) emitters and emitters that show preferential horizontal orientation of their transition dipole moment (TDM) are two emerging strategies to enhance the efficiency of OLEDs. We present the first example of a liquid crystalline multi-resonance TADF (MR-TADF) emitter, DiKTa-LC . The compound possesses a nematic liquid crystalline phase between 80 °C and 110 °C. Importantly, the TDM of the spin-coated film shows preferential horizontal orientation, with an anisotropy factor, a, of 0.28, which is preserved in doped poly(vinylcarbazole) films. Green-emitting (λEL=492 nm) solution-processed OLEDs based on DiKTa-LC showed an EQEmax of 13.6 %. We thus demonstrate for the first time how self-assembly of a liquid crystalline TADF emitter can lead to the so-far elusive control of the orientation of the transition dipole in solution-processed films, which will be of relevance for high-performance solution-processed OLEDs. 相似文献