Dokument-ID Dokumenttyp Verfasser/Autoren Herausgeber Haupttitel Abstract Auflage Verlagsort Verlag Erscheinungsjahr Seitenzahl Schriftenreihe Titel Schriftenreihe Bandzahl ISBN Quelle der Hochschulschrift Konferenzname Quelle:Titel Quelle:Jahrgang Quelle:Heftnummer Quelle:Erste Seite Quelle:Letzte Seite URN DOI Abteilungen OPUS4-55203 Wissenschaftlicher Artikel Reinicke, Stefan; Rees, Huw C.; Espeel, Pieter; Vanparijs, Nane; Bisterfeld, Carolin; Dick, Markus; Rosencrantz, Ruben R.; Brezesinski, Gerald; de Geest, Bruno G.; Du Prez, Filip E.; Pietruszka, Jörg; Böker, Alexander Immobilization of 2-Deoxy-D-ribose-5-phosphate Aldolase in Polymeric Thin Films via the Langmuir-Schaefer Technique A synthetic protocol for the fabrication of ultrathin polymeric films containing the enzyme 2-deoxy-D-ribose-5-phosphate aldolase from Escherichia coli (DERA(EC)) is presented. Ultrathin enzymatically active films are useful for applications in which only small quantities of active material are needed and at the same time quick response and contact times without diffusion limitation are wanted. We show how DERA as an exemplary enzyme can be immobilized in a thin polymer layer at the air-water interface and transferred to a suitable support by the Langmuir-Schaefer technique under full conservation of enzymatic activity. The polymer in use is a poly(N-isopropylacrylamide-co-N-2-thiolactone acrylamide) (P(NIPAAm-co-TlaAm)) statistical copolymer in which the thiolactone units serve a multitude of purposes including hydrophobization of the polymer, covalent binding of the enzyme and the support and finally cross-linking of the polymer matrix. The application of this type of polymer keeps the whole approach simple as additional cocomponents such as cross-linkers are avoided. Washington American Chemical Society 2017 10 ACS applied materials & interfaces 9 8317 8326 10.1021/acsami.6b13632 Institut für Biochemie und Biologie OPUS4-46466 Wissenschaftlicher Artikel Hentrich, Doreen; Taabache, Soraya; Brezesinski, Gerald; Lange, Nele; Unger, Wolfgang; Kuebel, Christian; Bertin, Annabelle; Taubert, Andreas A Dendritic Amphiphile for Efficient Control of Biomimetic Calcium Phosphate Mineralization The phase behavior of a dendritic amphiphile containing a Newkome-type dendron as the hydrophilic moiety and a cholesterol unit as the hydrophobic segment is investigated at the air-liquid interface. The amphiphile forms stable monomolecular films at the airliquid interface on different subphases. Furthermore, the mineralization of calcium phosphate beneath the monolayer at different calcium and phosphate concentrations versus mineralization time shows that at low calcium and phosphate concentrations needles form, whereas flakes and spheres dominate at higher concentrations. Energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and electron diffraction confirm the formation of calcium phosphate. High-resolution transmission electron microscopy and electron diffraction confirm the predominant formation of octacalcium phosphate and hydroxyapatite. The data also indicate that the final products form via a complex multistep reaction, including an association step, where nano-needles aggregate into larger flake-like objects. Weinheim Wiley-VCH 2017 14 Macromolecular bioscience 17 2541 2548 10.1002/mabi.201600524 Institut für Biochemie und Biologie OPUS4-46217 Wissenschaftlicher Artikel Hentrich, Doreen; Brezesinski, Gerald; Kuebel, Christian; Bruns, Michael; Taubert, Andreas Cholesteryl Hemisuccinate Monolayers Efficiently Control Calcium Phosphate Nucleation and Growth The article describes the phase behavior of cholesteryl hemisuccinate at the air-liquid interface and its effect on calcium phosphate (CP) mineralization. The amphiphile forms stable monolayers with phase transitions at the air-liquid interface from a gas to a tilted liquid-condensed (TLC) and finally to an untilted liquid-condensed (ULC) phase. CP mineralization beneath these monolayers leads to crumpled CP layers made from individual plates. The main crystal phase is octacalcium phosphate (OCP) along with a minor fraction of hydroxyapatite (HAP), as confirmed by X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, bright field transmission electron microscopy, and electron diffraction. Washington American Chemical Society 2017 11 Crystal growth & design : integrating the fields of crystal engineering and crystal growth for the synthesis and applications of new materials 17 5764 5774 10.1021/acs.cgd.7b00753 Institut für Chemie OPUS4-8953 Wissenschaftlicher Artikel Hentrich, Doreen; Junginger, Mathias; Bruns, Michael; Börner, Hans Gerhard; Brandt, Jessica; Brezesinski, Gerald; Taubert, Andreas Interface-controlled calcium phosphate mineralization The phase behavior of an amphiphilic block copolymer based on a poly(aspartic acid) hydrophilic block and a poly(n-butyl acrylate) hydrophobic block was investigated at the air-water and air-buffer interface. The polymer forms stable monomolecular films on both subphases. At low pH, the isotherms exhibit a plateau. Compression-expansion experiments and infrared reflection absorption spectroscopy suggest that the plateau is likely due to the formation of polymer bi- or multilayers. At high pH the films remain intact upon compression and no multilayer formation is observed. Furthermore, the mineralization of calcium phosphate beneath the monolayer was studied at different pH. The pH of the subphase and thus the polymer charge strongly affects the phase behavior of the film and the mineral formation. After 4 h of mineralization at low pH, atomic force microscopy shows smooth mineral films with a low roughness. With increasing pH the mineral films become inhomogeneous and the roughness increases. Transmission electron microscopy confirms this: at low pH a few small but uniform particles form whereas particles grown at higher pH are larger and highly agglomerated. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy confirm the formation of calcium phosphate. The levels of mineralization are higher in samples grown at high pH. London Royal Society of Chemistry 2015 12 CrystEngComm 17 6901 6913 10.1039/C4CE02274B Institut für Chemie OPUS4-39308 Wissenschaftlicher Artikel Hentrich, Doreen; Junginger, Mathias; Bruns, Michael; Boerner, Hans G.; Brandt, Jessica; Brezesinski, Gerald; Taubert, Andreas Interface-controlled calcium phosphate mineralization: effect of oligo(aspartic acid)-rich interfaces The phase behavior of an amphiphilic block copolymer based on a poly(aspartic acid) hydrophilic block and a poly(n-butyl acrylate) hydrophobic block was investigated at the air-water and air-buffer interface. The polymer forms stable monomolecular films on both subphases. At low pH, the isotherms exhibit a plateau. Compression-expansion experiments and infrared reflection absorption spectroscopy suggest that the plateau is likely due to the formation of polymer bi- or multilayers. At high pH the films remain intact upon compression and no multilayer formation is observed. Furthermore, the mineralization of calcium phosphate beneath the monolayer was studied at different pH. The pH of the subphase and thus the polymer charge strongly affects the phase behavior of the film and the mineral formation. After 4 h of mineralization at low pH, atomic force microscopy shows smooth mineral films with a low roughness. With increasing pH the mineral films become inhomogeneous and the roughness increases. Transmission electron microscopy confirms this: at low pH a few small but uniform particles form whereas particles grown at higher pH are larger and highly agglomerated. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy confirm the formation of calcium phosphate. The levels of mineralization are higher in samples grown at high pH. Cambridge Royal Society of Chemistry 2015 13 CrystEngComm 17 36 6901 6913 10.1039/c4ce02274b Institut für Chemie OPUS4-38142 Wissenschaftlicher Artikel Zakrevskyy, Yuriy; Roxlau, Julian; Brezesinski, Gerald; Lomadze, Nino; Santer, Svetlana A. Photosensitive surfactants: Micellization and interaction with DNA Recently, photosensitive surfactants have re-attracted considerable attention. It has been shown that their association with oppositely charged biologically important polyelectrolytes, such as DNA or microgels, can be efficiently manipulated simply by light exposure. In this article, we investigate the self-assembly of photosensitive surfactants as well as their interactions with DNA by calorimetric and spectroscopic methods. Critical micelle concentration (CMC), standard micellization enthalpy, entropy, and Gibbs energy were determined in different conditions (ionic strengths and temperatures) for a series of cationic surfactants with an azobenzene group in their tail. It is shown, that aggregation forces of photosensitive units play an important role in the micellization giving the major contribution to the micellization enthalpy. The onset of the aggregation can be traced from shift of the absorption peak position in the UV-visible spectrum. Titration UV-visible spectroscopy is used as an alternative, simple, and sensitive approach to estimate CMC. The titration UV-visible spectroscopy was also employed to investigate interactions (CAC: critical aggregation concentration, precipitation, and colloidal stabilization) in the DNA-surfactant complex. Melville American Institute of Physics 2014 8 The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr 140 4 10.1063/1.4862678 Institut für Physik und Astronomie OPUS4-46830 Wissenschaftlicher Artikel Teixeira, C. V.; Blanzat, Muriel; Koetz, Joachim; Rico-Lattes, I.; Brezesinski, Gerald In-plane miscibility and mixed bilayer microstructure in mixtures of catanionic glycolipids and zwitterionic phospholipids SAXS/WAXS studies were performed in combination with freeze fracture electron microscopy using mixtures of a new Gemini catanionic surfactant (Gem 16-12, formed by two sugar groups bound by a hydrocarbon spacer with 12 carbons and two 16-carbon chains) and the zwitterionic phospholipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine(DPPC) to establish the phase diagram. Gem 16-12 in water forms bilayers with the same amount of hydration water as DPPC. A frozen interdigitated phase with a low hydration number is observed below room temperature. The kinetics of the formation of this crystalline phase is very slow. Above the chain melting temperature, multilayered vesicles are formed. Mixing with DPPC produces mixed bilayers above the corresponding chain melting temperature. At room temperature, partially lamellar aggregates with local nematic order are observed. Splitting of infinite lamellae into discs is linked to immiscibility in frozen state. The ordering process is always accompanied by dehydration of the system. As a consequence, an unusual order-disorder phase transition upon cooling is observed. Amsterdam Elsevier 2006 12 Biochimica et biophysica acta : Biomembranes 1758 1797 1808 10.1016/j.bbamem.2006.05.025 Institut für Chemie OPUS4-18193 Wissenschaftlicher Artikel Poloucek, P.; Pietsch, Ullrich; Geue, Thomas; Symietz, Christian; Brezesinski, Gerald X-ray reflectivity analysis of thin complex Langmuir-Blodgett films 2001 Institut für Physik und Astronomie OPUS4-18265 Wissenschaftlicher Artikel Pietsch, Ullrich; Grenzer, Jörg; Geue, Thomas; Neißendorfer, Frank; Brezesinski, Gerald; Symietz, Christian; Möhwald, Helmuth; Gudat, Wolfgang The energy dispersive reflectometer at BESSY II : a challenge for thin film analysis 2001 Institut für Physik und Astronomie OPUS4-20783 Wissenschaftlicher Artikel Struth, Bernd; Decher, Gero; Schmitt, J.; Hofmeister, Wolfgang; Neißendorfer, Frank; Pietsch, Ullrich; Brezesinski, Gerald; Möhwald, Helmuth Chemical modification of Topaz surfaces 1999 Institut für Physik und Astronomie