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991.
Laurens D. B. Mandemaker Miguel Rivera-Torrente Guusje Delen Dr. Jan P. Hofmann Dr. Matthias Lorenz Dr. Alex Belianinov Prof. Dr. Bert M. Weckhuysen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(3):691-698
Metal–organic frameworks (MOFs) are a promising class of materials for many applications, due to their high chemical tunability and superb porosity. By growing MOFs as (thin-)films, additional properties and potential applications become available. Here, copper (II) 1,3,5-benzenetricarboxylate (Cu-BTC) metal–organic framework (MOF) thin-films are reported, which were synthesized by spin-coating, resulting in “nanowebs”, that is, fiber-like structures. These surface-mounted MOFs (SURMOFs) were studied by using photoinduced force microscopy (PiFM) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The optimal concentration of precursors (10 mm ) was determined that resulted in chemically homogeneous, pure nanowebs. Furthermore, the morphology and (un)coordinated Cu sites in the web were tuned by varying the rotation speed of the spin-coating process. X-ray diffraction (XRD) analysis showed that rotation speeds ≥2000 rpm (with precursors in a water/ethanol solution) generate the catena-triaqua-μ-(1,3,5-benzenetricarboxylate)-copper(II), or Cu(BTC)(H2O)3 coordination polymer. X-ray photoelectron spectroscopy (XPS) highlighted the strong decrease in number of (defective) Cu+ sites, as the nanowebs mainly consist of coordinated Cu2+ Lewis acid sites (LAS) and organic linker–linker, for example, hydrogen-bonding, interactions. Finally, the Lewis-acidic character of the Cu sites is illustrated by testing the films as catalysts in the isomerization of α-pinene oxide. The higher number of LAS (≥3000 rpm), result in higher campholenic aldehyde selectivity reaching up to 87.7 %. Furthermore, the strength of a combined micro- and spectroscopic approach in understanding the nature of MOF thin-films in a spatially resolved manner is highlighted. 相似文献
992.
993.
Tao Wang Dr. Yuzhou Wu Dr. Seah Ling Kuan Oliver Dumele Dr. Markus Lamla Dr. David Y. W. Ng Matthias Arzt Jessica Thomas Jan O. Mueller Prof. Dr. Christopher Barner‐Kowollik Prof. Dr. Tanja Weil 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(1):228-238
A disulfide intercalator toolbox was developed for site‐specific attachment of a broad variety of functional groups to proteins or peptides under mild, physiological conditions. The peptide hormone somatostatin (SST) served as model compound for intercalation into the available disulfide functionalization schemes starting from the intercalator or the reactive SST precursor before or after bioconjugation. A tetrazole–SST derivative was obtained that undergoes photoinduced cycloaddition in mammalian cells, which was monitored by live‐cell imaging. 相似文献
994.
Daniel Josef Bell Monika Wiese Ariel Augusto Schönberger Matthias Wessling 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(37):16181-16187
Metal–organic frameworks (MOFs) are suitable enzyme immobilization matrices. Reported here is the in situ biomineralization of glucose oxidase (GOD) into MOF crystals (ZIF-8) by interfacial crystallization. This method is effective for the selective coating of porous polyethersulfone microfiltration hollow fibers on the shell side in a straightforward one-step process. MOF layers with a thickness of 8 μm were synthesized, and fluorescence microscopy and a colorimetric protein assay revealed the successful inclusion of GOD into the ZIF-8 layer with an enzyme concentration of 29±3 μg cm−2. Enzymatic activity tests revealed that 50 % of the enzyme activity is preserved. Continuous enzymatic reactions, by the permeation of β-d -glucose through the GOD@ZIF-8 membranes, showed a 50 % increased activity compared to batch experiments, emphasizing the importance of the convective transport of educts and products to and from the enzymatic active centers. 相似文献
995.
Phase field models recently gained a lot of interest in the context of tumour growth models. Typically Darcy-type flow models are coupled to Cahn–Hilliard equations. However, often Stokes or Brinkman flows are more appropriate flow models. We introduce and mathematically analyse a new Cahn–Hilliard–Brinkman model for tumour growth allowing for chemotaxis. Outflow boundary conditions are considered in order not to influence tumour growth by artificial boundary conditions. Existence of global-in-time weak solutions is shown in a very general setting. 相似文献
996.
Steffen Pospiech Dr. Michael Bolte Dr. Hans‐Wolfram Lerner Prof. Dr. Matthias Wagner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8229-8236
9,10‐(Bpin)2‐anthracene ( 3 , HBpin=pinacolborane) was synthesized from 9,10‐dibromoanthracene in a stepwise lithiation/borylation sequence. The reaction of 3 with highly activated magnesium furnished the diborylated magnesium anthracene 4 , which was quenched in situ with ethereal HCl to yield cis‐9,10‐(Bpin)2‐DHA (cis‐ 5 , DHA=9,10‐dihydroanthracene). Compound cis‐ 5 , in turn, can be reduced with Li[AlH4] in THF to give its diborate Li2[cis‐9,10‐(BH3)2‐DHA] (Li2[cis‐ 6 ]). In the crystal lattice, the THF solvate Li2[cis‐ 6 ] ? 3 THF establishes a dimeric structure with Li‐(μ‐H)‐B coordination modes. Hydride abstraction from Li2[cis‐ 6 ] with Me3SiCl yields the B?H?B‐bridged DHA Li[ 7 ]. This product can also be viewed as a unique cyclic B2H7? derivative with a hydrocarbon backbone. Treatment of Li2[cis‐ 6 ] with the stronger hydride abstracting agent Me3SiOTf (HOTf=trifluoromethanesulfonic acid) in THF affords the THF diadduct of cis‐9,10‐(BH(OTf))2‐DHA. 相似文献
997.
998.
999.
Tatyana Kovshova Nadezhda Osipova Anna Alekseeva Julia Malinovskaya Alexey Belov Andrey Budko Galina Pavlova Olga Maksimenko Shakti Nagpal Svenja Braner Harshvardhan Modh Vadim Balabanyan Matthias G. Wacker Svetlana Gelperina 《Molecules (Basel, Switzerland)》2021,26(4)
Targeted delivery of doxorubicin still poses a challenge with regards to the quantities reaching the target site as well as the specificity of the uptake. In the present approach, two colloidal nanocarrier systems, NanoCore-6.4 and NanoCore-7.4, loaded with doxorubicin and characterized by different drug release behaviors were evaluated in vitro and in vivo. The nanoparticles utilize a specific surface design to modulate the lipid corona by attracting blood-borne apolipoproteins involved in the endogenous transport of chylomicrons across the blood–brain barrier. When applying this strategy, the fine balance between drug release and carrier accumulation is responsible for targeted delivery. Drug release experiments in an aqueous medium resulted in a difference in drug release of approximately 20%, while a 10% difference was found in human serum. This difference affected the partitioning of doxorubicin in human blood and was reflected by the outcome of the pharmacokinetic study in rats. For the fast-releasing formulation NanoCore-6.4, the AUC0→1h was significantly lower (2999.1 ng × h/mL) than the one of NanoCore-7.4 (3589.5 ng × h/mL). A compartmental analysis using the physiologically-based nanocarrier biopharmaceutics model indicated a significant difference in the release behavior and targeting capability. A fraction of approximately 7.310–7.615% of NanoCore-7.4 was available for drug targeting, while for NanoCore-6.4 only 5.740–6.057% of the injected doxorubicin was accumulated. Although the targeting capabilities indicate bioequivalent behavior, they provide evidence for the quality-by-design approach followed in formulation development. 相似文献
1000.
Lea Kremer Elisabeth Hennes Alexandra Brause Andrei Ursu Lucas Robke Hideaki T. Matsubayashi Yuta Nihongaki Jana Flegel Ivana Mejdrov Jan Eickhoff Matthias Baumann Radim Nencka Petra Janning Susanne Kordes Hans R. Schler Jared Sterneckert Takanari Inoue Slava Ziegler Herbert Waldmann 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(46):16770-16781