Ferrocenyl Glycidyl Ether: A Versatile Ferrocene Monomer for Copolymerization with Ethylene Oxide to Water-Soluble, Thermoresponsive Copolymers

The first ferrocene-containing epoxide monomer, ferrocenyl glycidyl ether (fcGE), is introduced. The monomer has been copolymerized with ethylene oxide (EO). This leads to electroactive, water-soluble, and thermoresponsive poly(ethylene glycol) (PEG) derived copolyethers. Anionic homo- and copolymerization of fcGE with EO was possible. Molecular weights could be varied from 2000 to 10 000 g mol–1, resulting in polymers with narrow molecular weight distribution (Mw/Mn = 1.07–1.20). The ferrocene (fc) content was varied from 3 to 30 mol %, obtaining water-soluble materials up to 10 mol % incorporation of the apolar ferrocenyl comonomer. Despite the steric bulk of fcGE, random copolymers were …

Signalling codes for the maintenance and lineage commitment of embryonic gastric epithelial progenitors

The identity of embryonic gastric epithelial progenitors is unknown. We used single-cell RNA sequencing, genetic lineage tracing and organoid assays to assess whether Axin2 and Lgr5 expressing cells are gastric progenitors in the developing mouse stomach. We show that Axin2+ cells represent a transient population of embryonic epithelial cells in the forestomach. Lgr5+ cells generate both glandular corpus and squamous forestomach organoids ex vivo. Only Lgr5+ progenitors give rise to zymogenic cells in culture. Modulating the activity of the WNT, BMP and Notch pathways in vivo and ex vivo, we found that WNTs are essential for the maintenance of Lgr5+ epithelial cells. Notch prevents differen…

Back Cover: Nanographenes: Ultrastable, Switchable, and Bright Probes for Super‐Resolution Microscopy (Angew. Chem. Int. Ed. 1/2020)

Nanographene: ultrastabile, schaltbare und helle Sonden für die hochauflösende Mikroskopie

High-resolution deep view microscopy of cells and tissues

Abstract Methods, experimental setups and perspectives of three-dimensional deep view imaging microscopy of cell or tissue samples are reported. Preliminary biophysical and clinically relevant examples are presented.

Extending the infrared limit of oxygenic photosynthesis

Rücktitelbild: Nanographene: ultrastabile, schaltbare und helle Sonden für die hochauflösende Mikroskopie (Angew. Chem. 1/2020)

Nanoprobing the acidification process during intracellular uptake and trafficking

Abstract Many nanoparticular drug delivery approaches rely on a detailed knowledge of the acidification process during intracellular trafficking of endocytosed nanoparticles (NPs). Therefore we produced a nanoparticular pH sensor composed of the fluorescent pH-sensitive dual wavelength dye carboxy seminaphthorhodafluor-1 (carboxy SNARF-1) coupled to the surface of amino-functionalized polystyrene NPs (SNARF-1-NP). By applying a calibration fit function to confocal laser scanning microscopy (CLSM) images, local pH values were determined. The acidification and ripening process of endo/lysosomal compartments containing nanoparticles was followed over time and was found to progress up to 6h to …

Ultralow-intensity near-infrared light induces drug delivery by upconverting nanoparticles

Mesoporous silica coated upconverting nanoparticles are loaded with the anticancer drug doxorubicin and grafted with ruthenium complexes as photoactive molecular valves. Drug release was triggered by 974 nm light with 0.35 W cm(-2). Such low light intensity minimized overheating problems and prevented photodamage to biological samples.

Microstructure analysis of biocompatible phosphoester copolymers

Copolymers with varying compositions of 2-ethoxy-2-oxo-1,3,2-dioxaphospholane (EEP) and 2-ethoxy-4-methyl-2-oxo-1,3,2-dioxaphospholane (EMEP) have been synthesized via 1,5,7-triazabicyclo[4.4.0]dec-5-ene-catalyzed anionic ring-opening polymerization. The molecular weights and comonomer ratios were well controlled and polymers with reasonable molecular weight distributions (<1.5) were obtained in all cases. The copolymers were investigated by 1H and 31P NMR spectroscopies to determine the underlying microstructure via detailed dyad analysis. The copolymers were found to be nontoxic to HeLa cells. Furthermore, the obtained copolymers of EEP and EMEP show thermoresponsive properties, i.e., exh…

The Nonbilayer Lipid MGDG and the Major Light-Harvesting Complex (LHCII) Promote Membrane Stacking in Supported Lipid Bilayers.

The thylakoid membrane of algae and land plants is characterized by its intricate architecture, comprising tightly appressed membrane stacks termed grana. The contributions of individual components to grana stack formation are not yet fully elucidated. As an in vitro model, we use supported lipid bilayers made of thylakoid lipid mixtures to study the effect of major light-harvesting complex (LHCII), different lipids, and ions on membrane stacking, seen as elevated structures forming on top of the planar membrane surface in the presence of LHCII protein. These structures were examined by confocal laser scanning microscopy, atomic force microscopy, and fluorescence recovery after photobleachi…

Cover Picture: Design, Synthesis, and Miniemulsion Polymerization of New Phosphonate Surfmers and Application Studies of the Resulting Nanoparticles as Model Systems for Biomimetic Mineralization and Cellular Uptake (Chem. Eur. J. 17/2012)

NECAB2 participates in an endosomal pathway of mitochondrial stress response at striatal synapses

Synaptic signaling depends on ATP generated by mitochondria. Due to extensive connectivity, the striatum is especially vulnerable to mitochondrial dysfunction and thus requires efficient mitochondrial quality control. We found that the neuronal calcium-binding protein NECAB2 ensures synaptic function in the striatum by increasing mitochondrial efficiency. NECAB2 associates with early endosomes and mitochondria at striatal synapses. Loss of NECAB2 dysregulates proteins of the endosomal ESCRT machinery and oxidative phosphorylation. Mitochondria from NECAB2-deficient mice are more abundant but less efficient. These mitochondria exhibit increased respiration and superoxide production but produ…

Cationized albumin-biocoatings for the immobilization of lipid vesicles

Tethered lipid membranes or immobilized lipid vesicles are frequently used as biomimetic systems. In this article, the authors presented a suitable method for efficient immobilization of lipid vesicles onto a broad range of surfaces, enabling analysis by quantitative methods even under rigid, mechanical conditions-bare surfaces such as hydrophilic glass surfaces as well as hydrophobic polymer slides or metal surfaces such as gold. The immobilization of vesicles was based on the electrostatic interaction of zwitterionic or negatively charged lipid vesicles with two types of cationic chemically modified bovine serum albumin (cBSA) blood plasma proteins (cBSA-113 and cBSA-147). Quantitative an…

Nanographenes: Ultrastable, Switchable, and Bright Probes for Super-Resolution Microscopy.

Abstract Super‐resolution fluorescence microscopy has enabled important breakthroughs in biology and materials science. Implementations such as single‐molecule localization microscopy (SMLM) and minimal emission fluxes (MINFLUX) microscopy in the localization mode exploit fluorophores that blink, i.e., switch on and off, stochastically. Here, we introduce nanographenes, namely large polycyclic aromatic hydrocarbons that can also be regarded as atomically precise graphene quantum dots, as a new class of fluorophores for super‐resolution fluorescence microscopy. Nanographenes exhibit outstanding photophysical properties: intrinsic blinking even in air, excellent fluorescence recovery, and sta…