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- ItemAnti-correlation of HER2 and focal adhesion complexes in the plasma membrane(San Francisco : Public Library of Science, 2020) Weinberg, F.; Han, M.K.L.; Dahmke, I.N.; Campo, A.D.; de Jonge, N.Excess presence of the human epidermal growth factor receptor 2 (HER2) as well as of the focal adhesion protein complexes are associated with increased proliferation, migratory, and invasive behavior of cancer cells. A cross-regulation between HER2 and integrin signaling pathways has been found, but the exact mechanism remains elusive. Here, we investigated whether HER2 colocalizes with focal adhesion complexes on breast cancer cells overexpressing HER2. For this purpose, vinculin or talin green fluorescent protein (GFP) fusion proteins, both key constituents of focal adhesions, were expressed in breast cancer cells. HER2 was either extracellularly or intracellularly labeled with fluorescent quantum dots nanoparticles (QDs). The cell-substrate interface was analyzed at the location of the focal adhesions by means of total internal reflection fluorescent microscopy or correlative fluorescence- and scanning transmission electron microscopy. Expression of HER2 at the cell-substrate interface was only observed upon intracellular labeling, and was heterogeneous with both HER2-enriched and -low regions. In contrast to an expected enrichment of HER2 at focal adhesions, an anti-correlated expression pattern was observed for talin and HER2. Our findings suggest a spatial anti-correlation between HER2 and focal adhesion complexes for adherent cells.
- ItemEnantiomer-selective magnetization of conglomerates for quantitative chiral separation(Berlin : Springer Nature, 2019) Ye, X.; Cui, J.; Li, B.; Li, N.; Wang, R.; Yan, Z.; Tan, J.; Zhang, J.; Wan, X.Selective crystallization represents one of the most economical and convenient methods to provide large-scale optically pure chiral compounds. Although significant development has been achieved since Pasteur’s separation of sodium ammonium tartrate in 1848, this method is still fundamentally low efficient (low transformation ratio or high labor). Herein, we describe an enantiomer-selective-magnetization strategy for quantitatively separating the crystals of conglomerates by using a kind of magnetic nano-splitters. These nano-splitters would be selectively wrapped into the S-crystals, leading to the formation of the crystals with different physical properties from that of R-crystals. As a result of efficient separation under magnetic field, high purity chiral compounds (99.2 ee% for R-crystals, 95.0 ee% for S-crystals) can be obtained in a simple one-step crystallization process with a high separation yield (95.1%). Moreover, the nano-splitters show expandability and excellent recyclability. We foresee their great potential in developing chiral separation methods used on different scales. © 2019, The Author(s).
- ItemMorphology controlled preparation of monodisperse TiO2 nanorods and nanoparticles for optical nanocomposites(Saarbrücke : Leibniz-Institut für Neue Materialien, 2011) Bentz, Dirk; Becker-Willinger, Carsten; Schmitz-Stöwe, Sabine; Veith, MichaelAnatase nanoparticles and nanorods were obtained through a modified sol-gel route from titanium(IV) bis(acetylacetonate) diisopropoxide. For particle synthesis a mixture of oleic acid and oleyl amine has been used which offers not only control on particle morphology but also provides organically capped surface modified particles, which can be readily mixed with acrylic monomers yielding completely transparent dispersions. UV- and thermal curing of the monomer / particle mixture lead to clear coatings without any nanoparticle agglomeration.
- ItemTargeted delivery of functionalized PLGA nanoparticles to macrophages by complexation with the yeast Saccharomyces cerevisiae(Chichester : John Wiley and Sons Ltd, 2020) Kiefer, R.; Jurisic, M.; Dahlem, C.; Koch, M.; Schmitt, M.J.; Kiemer, A.K.; Schneider, M.; Breinig, F.Nanoparticles (NPs) are able to deliver a variety of substances into eukaryotic cells. However, their usage is often hampered by a lack of specificity, leading to the undesired uptake of NPs by virtually all cell types. In contrast to this, yeast is known to be specifically taken up into immune cells after entering the body. Therefore, we investigated the interaction of biodegradable surface-modified poly(lactic-co-glycolic acid) (PLGA) particles with yeast cells to overcome the unspecificity of the particulate carriers. Cells of different Saccharomyces cerevisiae strains were characterized regarding their interaction with PLGA-NPs under isotonic and hypotonic conditions. The particles were shown to efficiently interact with yeast cells leading to stable NP/yeast-complexes allowing to associate or even internalize compounds. Notably, applying those complexes to a coculture model of HeLa cells and macrophages, the macrophages were specifically targeted. This novel nano-in-micro carrier system suggests itself as a promising tool for the delivery of biologically active agents into phagocytic cells combining specificity and efficiency.