TY - JOUR A1 - Shkilnyy, Andriy A1 - Gräf, Ralph A1 - Hiebl, Bernhard A1 - Neffe, Axel T. A1 - Friedrich, Alwin A1 - Hartmann, Juergen A1 - Taubert, Andreas T1 - Unprecedented, low cytotoxicity of spongelike calcium phosphate/poly(ethylene imine) hydrogel composites N2 - Covalently crosslinked PEI hydrogels are efficient templates for calcium phosphate mineralization in SBF. In contrast to the PEI hydrogels, non-crosslinked PEI does not lead to calcium phosphate nucleation and growth in SBF. The precipitate is a mixture of brushite and hydroxyapatite. The PEI/calcium phosphate composite material exhibits a sponge like morphology and a chemical composition that is interesting for implants. Cytotoxicity tests using Dictyostelium discoideum amoebae show that both the non-mineralized and mineralized hydrogels have a very low cytotoxicity. This suggests that next generation PEI hydrogels, where also the degradation products are non-toxic, could be interesting for biomedical applications. Y1 - 2009 UR - http://www3.interscience.wiley.com/cgi-bin/jhome/77002860 U6 - https://doi.org/10.1002/mabi.200800266 SN - 1616-5187 ER - TY - JOUR A1 - Ihlenburg, Ramona A1 - Mai, Tobias A1 - Thünemann, Andreas F. A1 - Baerenwald, Ruth A1 - Saalwächter, Kay A1 - Koetz, Joachim A1 - Taubert, Andreas T1 - Sulfobetaine hydrogels with a complex multilength-scale hierarchical structure JF - The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces & biophysical chemistry N2 - Hydrogels with a hierarchical structure were prepared from a new highly water-soluble crosslinker N,N,N',N'-tetramethyl-N,N'-bis(2-ethylmethacrylate)-propyl-1,3-diammonium dibromide and from the sulfobetaine monomer 2-(N-3-sulfopropyl-N,N-dimethyl ammonium)ethyl methacrylate. The free radical polymerization of the two compounds is rapid and yields near-transparent hydrogels with sizes up to 5 cm in diameter. Rheology shows a clear correlation between the monomer-to-crosslinker ratio and the storage and loss moduli of the hydrogels. Cryo-scanning electron microscopy, low-field nuclear magnetic resonance (NMR) spectroscopy, and small-angle X-ray scattering show that the gels have a hierarchical structure with features spanning the nanometer to the sub-millimeter scale. The NMR study is challenged by the marked inhomogeneity of the gels and the complex chemical structure of the sulfobetaine monomer. NMR spectroscopy shows how these complications can be addressed via a novel fitting approach that considers the mobility gradient along the side chain of methacrylate-based monomers. KW - Defects KW - Hydrogels KW - Nuclear magnetic resonance spectroscopy KW - Scattering KW - X-ray scattering Y1 - 2021 U6 - https://doi.org/10.1021/acs.jpcb.0c10601 SN - 1520-6106 SN - 1520-5207 VL - 125 IS - 13 SP - 3398 EP - 3408 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Ihlenburg, Ramona A1 - Lehnen, Anne-Catherine A1 - Koetz, Joachim A1 - Taubert, Andreas T1 - Sulfobetaine Cryogels for Preferential Adsorption of Methyl Orange from Mixed Dye Solutions JF - Polymers / Molecular Diversity Preservation International N2 - New cryogels for selective dye removal from aqueous solution were prepared by free radical polymerization from the highly water-soluble crosslinker N,N,N’,N’-tetramethyl-N,N’-bis(2-ethylmethacrylate)-propyl-1,3-diammonium dibromide and the sulfobetaine monomer 2-(N-3-sulfopropyl-N,N-dimethyl ammonium)ethyl methacrylate. The resulting white and opaque cryogels have micrometer sized pores with a smaller substructure. They adsorb methyl orange (MO) but not methylene blue (MB) from aqueous solution. Mixtures of MO and MB can be separated through selective adsorption of the MO to the cryogels while the MB remains in solution. The resulting cryogels are thus candidates for the removal of hazardous organic substances, as exemplified by MO and MB, from water. Clearly, it is possible that the cryogels are also potentially interesting for removal of other compounds such as pharmaceuticals or pesticides, but this must be investigated further. KW - cryogel KW - water treatment KW - dye removal KW - methyl orange KW - methylene blue KW - dye mixture Y1 - 2020 U6 - https://doi.org/10.3390/polym13020208 SN - 2073-4360 VL - 13 IS - 2 PB - MDPI CY - Basel ER - TY - JOUR A1 - Lehmann, Frederike A1 - Franz, Alexandra A1 - Toebbens, Daniel M. A1 - Levcenco, Sergej A1 - Unold, Thomas A1 - Taubert, Andreas A1 - Schorr, Susan T1 - The phase diagram of a mixed halide (Br, I) hybrid perovskite obtained by synchrotron X-ray diffraction JF - RSC Advances N2 - By using synchrotron X-ray powder diffraction, the temperature dependent phase diagram of the hybrid perovskite tri-halide compounds, methyl ammonium lead iodide (MAPbI3, MA+ = CH3NH3+) and methyl ammonium lead bromide (MAPbBr3), as well as of their solid solutions, has been established. The existence of a large miscibility gap between 0.29 ≤ x ≤ 0.92 (±0.02) for the MAPb(I1−xBrx)3 solid solution has been proven. A systematic study of the lattice parameters for the solid solution series at room temperature revealed distinct deviations from Vegard's law. Furthermore, temperature dependent measurements showed that a strong temperature dependency of lattice parameters from the composition is present for iodine rich compositions. In contrast, the bromine rich compositions show an unusually low dependency of the phase transition temperature from the degree of substitution. Y1 - 2019 U6 - https://doi.org/10.1039/c8ra09398a SN - 2046-2069 VL - 9 IS - 20 SP - 11151 EP - 11159 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Draude, F. A1 - Galla, S. A1 - Pelster, Axel A1 - Tentschert, J. A1 - Jungnickel, H. A1 - Haase, Alfred A1 - Mantion, Alexandre A1 - Thuenemann, Andreas F. A1 - Taubert, Andreas A1 - Luch, A. A1 - Arlinghaus, H. F. T1 - ToF-SIMS and Laser-SNMS analysis of macrophages after exposure to silver nanoparticles JF - Surface and interface analysis : an international journal devoted to the development and application of techniques for the analysis surfaces, interfaces and thin films N2 - Silver nanoparticles (SNPs) are among the most commercialized nanoparticles because of their antibacterial effects. Besides being employed, e. g. as a coatingmaterial for sterile surfaces in household articles and appliances, the particles are also used in a broad range of medical applications. Their antibacterial properties make SNPs especially useful for wound disinfection or as a coating material for prostheses and surgical instruments. Because of their optical characteristics, the particles are of increasing interest in biodetection as well. Despite the widespread use of SNPs, there is little knowledge of their toxicity. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and laser post-ionization secondary neutral mass spectrometry (Laser-SNMS) were used to investigate the effects of SNPs on human macrophages derived from THP-1 cells in vitro. For this purpose, macrophages were exposed to SNPs. The SNP concentration ranges were chosen with regard to functional impairments of the macrophages. To optimize the analysis of the macrophages, a special silicon wafer sandwich preparation technique was employed; ToF-SIMS was employed to characterize fragments originating from macrophage cell membranes. With the use of this optimized sample preparation method, the SNP-exposed macrophages were analyzed with ToF-SIMS and with Laser-SNMS. With Laser-SNMS, the three-dimensional distribution of SNPs in cells could be readily detected with very high efficiency, sensitivity, and submicron lateral resolution. We found an accumulation of SNPs directly beneath the cell membrane in a nanoparticular state as well as agglomerations of SNPs inside the cells. KW - Laser-SNMS KW - ToF-SIMS KW - life sciences KW - imaging KW - nanoparticles KW - three-dimensional depth profiling Y1 - 2013 U6 - https://doi.org/10.1002/sia.4902 SN - 0142-2421 VL - 45 IS - 1 SP - 286 EP - 289 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Junginger, Mathias A1 - Kübel, Christian A1 - Schacher, Felix H. A1 - Müller, Axel H. E. A1 - Taubert, Andreas T1 - Crystal structure and chemical composition of biomimetric calcium phosphate nanofibers N2 - Calcium phosphate nanofibers with a diameter of only a few nanometers and a cotton-ball-like aggregate morphology have been reported several times in the literature. Although fiber formation seems reproducible in a variety of conditions, the crystal structure and chemical composition of the fibers have been elusive. Using scanning transmission electron microscopy, low dose electron (nano)diffraction, energy-dispersive X-ray spectroscopy, and energy- filtered transmission electron microscopy, we have assigned crystal structures and chemical compositions to the fibers. Moreover, we demonstrate that the mineralization process yields true polymer/calcium phosphate hybrid materials where the block copolymer template is closely associated with the calcium phosphate. Y1 - 2013 UR - http://pubs.rsc.org/en/content/articlepdf/2013/ra/c3ra23348k U6 - https://doi.org/10.1039/c3ra23348k ER - TY - JOUR A1 - Kim, Jiyong A1 - Kim, Yohan A1 - Park, Kyoungwon A1 - Boeffel, Christine A1 - Choi, Hyung-Seok A1 - Taubert, Andreas A1 - Wedel, Armin T1 - Ligand Effect in 1-Octanethiol Passivation of InP/ZnSe/ZnS Quantum Dots-Evidence of Incomplete Surface Passivation during Synthesis JF - Small : nano micro N2 - The lack of anionic carboxylate ligands on the surface of InP/ZnSe/ZnS quantum dots (QDs), where zinc carboxylate ligands can be converted to carboxylic acid or carboxylate ligands via proton transfer by 1-octanethiol, is demonstrated. The as-synthesized QDs initially have an under-coordinated vacancy surface, which is passivated by solvent ligands such as ethanol and acetone. Upon exposure of 1-octanethiol to the QD surface, 1-octanethiol effectively induces the surface binding of anionic carboxylate ligands (derived from zinc carboxylate ligands) by proton transfer, which consequently exchanges ethanol and acetone ligands that bind on the incomplete QD surface. These systematic chemical analyses, such as thermogravimetric analysis-mass spectrometry and proton nuclear magnetic resonance spectroscopy, directly show the interplay of surface ligands, and it associates with QD light-emitting diodes (QD-LEDs). It is believed that this better understanding can lead to industrially feasible QD-LEDs. KW - colloidal quantum dots KW - incomplete surface passivation KW - indium KW - phosphide KW - surface chemistry KW - thiol passivation Y1 - 2022 U6 - https://doi.org/10.1002/smll.202203093 SN - 1613-6810 SN - 1613-6829 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Herold, Heike M. A1 - Aigner, Tamara Bernadette A1 - Grill, Carolin E. A1 - Krüger, Stefanie A1 - Taubert, Andreas A1 - Scheibel, Thomas R. T1 - SpiderMAEn BT - recombinant spider silk-based hybrid materials for advanced energy technology JF - Bioinspired, Biomimetic and Nanobiomaterials N2 - A growing energy demand requires new and preferably renewable energy sources. The infinite availability of solar radiation makes its conversion into storable and transportable energy forms attractive for research as well as for the industry. One promising example of a transportable fuel is hydrogen (H-2), making research into eco-friendly hydrogen production meaningful. Here, a hybrid system was developed using newly designed recombinant spider silk protein variants as a template for mineralization with inorganic titanium dioxide and gold. These bioinspired organic/inorganic hybrid materials allow for hydrogen production upon light irradiation. To begin with, recombinant spider silk proteins bearing titanium dioxide and gold-binding moieties were created and processed into structured films. These films were modified with gold and titanium dioxide in order to produce a photocatalyst. Subsequent testing revealed hydrogen production as a result of light-induced hydrolysis of water. Therefore, the novel setup presented here provides access to a new principle of generating advanced hybrid materials for sustainable hydrogen production and depicts a promising platform for further studies on photocatalytic production of hydrogen, the most promising future fuel. KW - hybrid materials KW - hydrogen KW - photocatalysts Y1 - 2019 U6 - https://doi.org/10.1680/jbibn.18.00007 SN - 2045-9858 SN - 2045-9866 VL - 8 IS - 1 SP - 99 EP - 108 PB - ICE Publishing CY - Westminister 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 - JOUR A1 - Kirchhecker, Sarah A1 - Tröger-Müller, Steffen A1 - Bake, Sebastian A1 - Antonietti, Markus A1 - Taubert, Andreas A1 - Esposito, Davido T1 - Renewable pyridinium ionic liquids from the continuous hydrothermal decarboxylation of furfural-amino acid derived pyridinium zwitterions JF - Green chemistry N2 - Fully renewable pyridinium ionic liquids were synthesised via the hydrothermal decarboxylation of pyridinium zwitterions derived from furfural and amino acids in flow. The functionality of the resulting ionic liquid (IL) can be tuned by choice of different amino acids as well as different natural carboxylic acids as the counterions. A representative member of this new class of ionic liquids was successfully used for the synthesis of ionogels and as a solvent for the Heck coupling. Y1 - 2015 U6 - https://doi.org/10.1039/c5gc00913h SN - 1463-9262 SN - 1463-9270 VL - 8 IS - 17 SP - 4151 EP - 4156 PB - Royal Society of Chemistry CY - Cambridge ER -