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991.
Yun Liu Guangze Yang Song Jin Run Zhang Peng Chen Tengjisi Lianzhou Wang Dong Chen David A. Weitz Chun-Xia Zhao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(45):20240-20249
Understanding drug-release kinetics is critical for the development of drug-loaded nanoparticles. We developed a J-aggregate-based Förster-resonance energy-transfer (FRET) method to investigate the release of novel high-drug-loading (50 wt %) nanoparticles in comparison with low-drug-loading (0.5 wt %) nanoparticles. Single-dye-loaded nanoparticles form J-aggregates because of the high dye-loading (50 wt %), resulting in a large red-shift (≈110 nm) in the fluorescence spectrum. Dual-dye-loaded nanoparticles with high dye-loading using FRET pairs exhibited not only FRET but also a J-aggregate red-shift (116 nm). Using this J-aggregate-based FRET method, dye-core–polymer-shell nanoparticles showed two release processes intracellularly: the dissolution of the dye aggregates into dye molecules and the release of the dye molecules from the polymer shell. Also, the high-dye-loading nanoparticles (50 wt %) exhibited a slow release kinetics in serum and relatively quick release in cells, demonstrating their great potential in drug delivery. 相似文献
992.
Yu Jiang Xiang Li Prof. David R. Walt 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(41):18166-18171
Alkaline phosphatase (ALP) is an important biomarker, as high levels of ALP in blood can indicate liver disease or bone disorders. However, current clinical blood tests only measure the total concentration of ALP but are unable to distinguish enzyme isotypes. Here, we demonstrate a novel and rapid approach to profile various ALP isozymes in blood via a single-molecule-analysis platform. The microarray platform provides enzyme kinetics of hundreds of individual molecules at high throughput. Using these single molecule kinetics, we characterize the different activity profiles of ALP isotypes. By analyzing both healthy and disease samples, we found the single molecule activity distribution of ALP in serum reflects the health status of patients. This result demonstrates the potential utility of the method for improving the conventional ALP test, as well as for analyzing other enzymatic biomarkers, including enzyme isotypes. 相似文献
993.
A quantification method for imatinib (IM), its major metabolite N-desmethyl imatinib (NDI), and a degradation by-product was developed using CE–MS combined with an online concentration technique. The use of multiple reaction monitoring (MRM)–MS/MS further improved the sensitivity of this technology. Liquid–liquid extraction (LLE) using tertiary butyl methyl ether yielded high recovery and reproducibility for the pretreatment of serum samples. The recovery rate exceeded 83% for all three analytes, and was 90% for IM. To improve quantification results, a conductivity-induced online analyte concentration technique, field-amplified sample stacking (FASS), was used. The S/N ratios were improved at least 10-fold when compared with conventional capillary zone electrophoresis. The detection limits were 0.2 ng/mL for IM, 0.4 ng/mL for NDI, and 4 ng/mL for the degradation by-product. These results are superior to those previously obtained by other reported methods. The new method was validated in terms of its selectivity, intra- and interday repeatability and accuracy, and sample storage stability, following the guidelines issued by the European Medicines Agency. Considering the convenient pretreatment procedure (LLE), superior sensitivity, and fast analysis speed (<15 min), this method can be useful in the determination of imatinib levels in blood. 相似文献
994.
Celina Love Jan Steinkühler David T. Gonzales Naresh Yandrapalli Tom Robinson Rumiana Dimova Dr. T.-Y. Dora Tang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(15):6006-6013
In situ, reversible coacervate formation within lipid vesicles represents a key step in the development of responsive synthetic cellular models. Herein, we exploit the pH responsiveness of a polycation above and below its pKa, to drive liquid–liquid phase separation, to form single coacervate droplets within lipid vesicles. The process is completely reversible as coacervate droplets can be disassembled by increasing the pH above the pKa. We further show that pH-triggered coacervation in the presence of low concentrations of enzymes activates dormant enzyme reactions by increasing the local concentration within the coacervate droplets and changing the local environment around the enzyme. In conclusion, this work establishes a tunable, pH responsive, enzymatically active multi-compartment synthetic cell. The system is readily transferred into microfluidics, making it a robust model for addressing general questions in biology, such as the role of phase separation and its effect on enzymatic reactions using a bottom-up synthetic biology approach. 相似文献
995.
Yuesu Chen Gabriel Glotz Dr. David Cantillo Prof. Dr. C. Oliver Kappe 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(13):2973-2979
N-Demethylation of oxycodone is one of the key steps in the synthesis of important opioid antagonists like naloxone or analgesics like nalbuphine. The reaction is typically carried out using stoichiometric amounts of toxic and corrosive reagents. Herein, we present a green and scalable organophotocatalytic procedure that accomplishes the N-demethylation step using molecular oxygen as the terminal oxidant and an organic dye (rose bengal) as an effective photocatalyst. Optimization of the reaction conditions under continuous flow conditions using visible-light irradiation led to an efficient, reliable, and scalable process, producing noroxycodone hydrochloride in high isolated yield and purity after a simple workup. 相似文献
996.
Zian Tang Dr. Antony George Dr. Andreas Winter David Kaiser Christof Neumann Dr. Thomas Weimann Prof. Dr. Andrey Turchanin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(29):6473-6478
Field effect transistors (FETs) based on 2D materials are of great interest for applications in ultrathin electronic and sensing devices. Here we demonstrate the possibility to add optical switchability to graphene FETs (GFET) by functionalizing the graphene channel with optically switchable azobenzene molecules. The azobenzene molecules were incorporated to the GFET channel by building a van der Waals heterostructure with a carbon nanomembrane (CNM), which is used as a molecular interposer to attach the azobenzene molecules. Under exposure with 365 nm and 455 nm light, azobenzene molecules transition between cis and trans molecular conformations, respectively, resulting in a switching of the molecular dipole moment. Thus, the effective electric field acting on the GFET channel is tuned by optical stimulation and the carrier density is modulated. 相似文献
997.
Dennis A. Buschmann Dr. H. Martin Dietrich Dr. David Schneider Dr. Verena M. Birkelbach Dr. Christoph Stuhl Prof. Dr. Karl W. Törnroos Dr. Cäcilia Maichle-Mössmer Prof. Dr. Reiner Anwander 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(47):10834-10840
Tetramethylaluminato/halogenido(X) ligand exchange reactions in half-sandwich complexes [CpRLa(AlMe4)2] are feasible in non-coordinating solvents and provide access to large coordination clusters of the type [CpRLaX2]x. Incomplete exchange reactions generate the hexalanthanum clusters [CpR6La6X8(AlMe4)4] (CpR=Cp*=C5Me5, X=I; CpR=Cp′=C5H4SiMe3, X=Br, I). Treatment of [Cp*La(AlMe4)2] with two equivalents Me3SiI gave the nonalanthanum cluster [Cp*LaI2]9, while the exhaustive reaction of [Cp′La(AlMe4)2] with the halogenido transfer reagents Me3GeX and Me3SiX (X=I, Br, Cl) produced a series of monocyclopentadienyl rare-earth-metal clusters with distinct nuclearity. Depending on the halogenido ion size the homometallic clusters [Cp′LaCl2]10 and [Cp′LaX2]12 (X=Br, I) could be isolated, whereas different crystallization techniques led to the aggregation of clusters of distinct structural motifs, including the desilylated cyclopentadienyl-bridged cluster [(μ-Cp)2Cp′8La8I14] and the heteroaluminato derivative [Cp′10La10Br18(AlBr2Me2)2]. The use of the Cp′ ancillary ligand facilitates cluster characterization by means of NMR spectroscopy. 相似文献
998.
David Rombach Hans‐Achim Wagenknecht 《Angewandte Chemie (International ed. in English)》2020,59(1):300-303
SF6 was applied as pentafluorosulfanylation reagent to prepare ethers with a vicinal SF5 substituent through a one‐step method involving photoredox catalysis. This method shows a broad substrate scope with respect to applicable alcohols for the conversion of α‐methyl and α‐phenyl styrenes. The products bear a new structural motif with two functional groups installed in one step. The alkoxy group allows elimination and azidation as further transformations into valuable pentafluorosulfanylated compounds. These results confirm that non‐toxic SF6 is a useful SF5 transfer reagent if properly activated by photoredox catalysis, and toxic reagents are completely avoided. In combination with light as an energy source, a high level of sustainability is achieved. Through this method, the proposed potential of the SF5 substituent in medicinal chemistry, agrochemistry, and materials chemistry may be exploited in the future. 相似文献
999.
Serhii Krykun Maksym Dekhtiarenko David Canevet Vincent Carr Frdric Aubriet Eric Levillain Magali Allain Zoia Voitenko Marc Sall Sbastien Goeb 《Angewandte Chemie (International ed. in English)》2020,59(2):716-720
Developing methodologies for on‐demand control of the release of a molecular guest requires the rational design of stimuli‐responsive hosts with functional cavities. While a substantial number of responsive metallacages have already been described, the case of coordination‐tweezers has been less explored. Herein, we report the first example of a redox‐triggered guest release from a metalla‐assembled tweezer. This tweezer incorporates two redox‐active panels constructed from the electron‐rich 9‐(1,3‐dithiol‐2‐ylidene)fluorene unit that are facing each other. It dimerizes spontaneously in solution and the resulting interpenetrated supramolecular structure can dissociate in the presence of an electron‐poor planar unit, forming a 1:1 host–guest complex. This complex dissociates upon tweezer oxidation/dimerization, offering an original redox‐triggered molecular delivery pathway. 相似文献
1000.
David A. Burns Eric M. Press M. A. Siegler Rebekka S. Klausen V. Sara Thoi 《Angewandte Chemie (International ed. in English)》2020,59(2):763-768
We report the synthesis of a set of 2D metal–organic frameworks (MOFs) constructed with organosilicon‐based linkers. These oligosilyl MOFs feature linear SinMe2n(C6H4CO2H)2 ligands (lin‐Sin, n=2, 4) connected by Cu paddlewheels. The stacking arrangement of the 2D sheets is dictated by van der Waals interactions and is tunable by solvent exchange, leading to reversible structural transformations between many crystalline and amorphous phases. 相似文献