TY - JOUR A1 - Hentrich, Doreen A1 - Brezesinski, Gerald A1 - Kuebel, Christian A1 - Bruns, Michael A1 - Taubert, Andreas T1 - Cholesteryl Hemisuccinate Monolayers Efficiently Control Calcium Phosphate Nucleation and Growth JF - Crystal growth & design : integrating the fields of crystal engineering and crystal growth for the synthesis and applications of new materials N2 - 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. Y1 - 2017 U6 - https://doi.org/10.1021/acs.cgd.7b00753 SN - 1528-7483 SN - 1528-7505 VL - 17 SP - 5764 EP - 5774 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Teixeira, C. V. A1 - Blanzat, Muriel A1 - Koetz, Joachim A1 - Rico-Lattes, I. A1 - Brezesinski, Gerald T1 - In-plane miscibility and mixed bilayer microstructure in mixtures of catanionic glycolipids and zwitterionic phospholipids JF - Biochimica et biophysica acta : Biomembranes N2 - 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. KW - SAXS KW - bilayer KW - gemini surfactant KW - ordering process KW - Anti-HIV KW - miscibility Y1 - 2006 U6 - https://doi.org/10.1016/j.bbamem.2006.05.025 SN - 0005-2736 VL - 1758 SP - 1797 EP - 1808 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Hentrich, Doreen A1 - Junginger, Mathias A1 - Bruns, Michael A1 - Börner, Hans Gerhard A1 - Brandt, Jessica A1 - Brezesinski, Gerald A1 - Taubert, Andreas T1 - Interface-controlled calcium phosphate mineralization BT - effect of oligo(aspartic acid)-rich interfaces JF - CrystEngComm N2 - 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. Y1 - 2015 U6 - https://doi.org/10.1039/C4CE02274B SN - 1466-8033 IS - 17 SP - 6901 EP - 6913 PB - Royal Society of Chemistry CY - London ER - TY - GEN A1 - Hentrich, Doreen A1 - Junginger, Mathias A1 - Bruns, Michael A1 - Börner, Hans Gerhard A1 - Brandt, Jessica A1 - Brezesinski, Gerald A1 - Taubert, Andreas T1 - Interface-controlled calcium phosphate mineralization BT - effect of oligo(aspartic acid)-rich interfaces N2 - 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. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 213 Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-89540 SP - 6901 EP - 6913 ER - TY - JOUR A1 - Hentrich, Doreen A1 - Junginger, Mathias A1 - Bruns, Michael A1 - Boerner, Hans G. A1 - Brandt, Jessica A1 - Brezesinski, Gerald A1 - Taubert, Andreas T1 - Interface-controlled calcium phosphate mineralization: effect of oligo(aspartic acid)-rich interfaces JF - CrystEngComm N2 - 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. Y1 - 2015 U6 - https://doi.org/10.1039/c4ce02274b SN - 1466-8033 VL - 17 IS - 36 SP - 6901 EP - 6913 PB - Royal Society of Chemistry CY - Cambridge ER -