TY  - GEN
A1  - Mehrabi, Pedram
A1  - Schulz, Eike
A1  - Müller-Werkmeister, Henrike
A1  - Persch, Elke
A1  - De Gasparo, Raoul
A1  - Diederich, Francois
A1  - Tellkamp, Friedjof
A1  - Pai, Emil F.
A1  - Miller, R. J. Dwayne
T1  - Time-resolved crystallography via an interlacing approach allows elucidation of milliseconds to seconds time delays
T2  - Acta Crystallographica Section A
KW  - Time-resolved crystallography
KW  - crystallography
KW  - enzymology
KW  - method development
Y1  - 2018
U6  - https://doi.org/10.1107/S205327331809321X
SN  - 2053-2733
VL  - 74
SP  - E138
EP  - E138
PB  - International Union of Crystallography
CY  - Chester
ER  - 
TY  - JOUR
A1  - Holland-Moritz, Henry
A1  - Graupner, Julia
A1  - Möller, Wolfhard
A1  - Pacholski, Claudia
A1  - Ronning, Carsten
T1  - Dynamics of nanoparticle morphology under low energy ion irradiation
JF  - Nanotechnology
N2  - If nanostructures are irradiated with energetic ions, the mechanism of sputtering becomes important when the ion range matches about the size of the nanoparticle. Gold nanoparticles with diameters of similar to 50 nm on top of silicon substrates with a native oxide layer were irradiated by gallium ions with energies ranging from 1 to 30 keV in a focused ion beam system. High resolution in situ scanning electron microscopy imaging permits detailed insights in the dynamics of the morphology change and sputter yield. Compared to bulk-like structures or thin films, a pronounced shaping and enhanced sputtering in the nanostructures occurs, which enables a specific shaping of these structures using ion beams. This effect depends on the ratio of nanoparticle size and ion energy. In the investigated energy regime, the sputter yield increases at increasing ion energy and shows a distinct dependence on the nanoparticle size. The experimental findings are directly compared to Monte Carlo simulations obtained from iradina and TRI3DYN, where the latter takes into account dynamic morphological and compositional changes of the target.
KW  - ion beam
KW  - nanoparticles
KW  - sputtering
KW  - Monte Carlo
KW  - in situ
Y1  - 2018
U6  - https://doi.org/10.1088/1361-6528/aac36c
SN  - 0957-4484
SN  - 1361-6528
VL  - 29
IS  - 31
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Mertens, Monique
A1  - Hilsch, Malte
A1  - Haralampiev, Ivan
A1  - Volkmer, Rudolf
A1  - Wessig, Pablo
A1  - Müller, Peter
T1  - Synthesis and characterization of a new Bifunctionalized, Fluorescent, and Amphiphilic molecule for recruiting SH-Containing molecules to membranes
JF  - ChemBioChem
N2  - This study describes the synthesis and characterization of an amphiphilic construct intended to recruit SH-containing molecules to membranes. The construct consists of 1)an aliphatic chain to enable anchoring within membranes, 2)a maleimide moiety to react with the sulfhydryl group of a soluble (bio)molecule, and 3)a fluorescence moiety to allow the construct to be followed by fluorescence spectroscopy and microscopy. It is shown that the construct can be incorporated into preformed membranes, thus allowing application of the approach with biological membranes. The close proximity between the fluorophore and the maleimide moiety within the construct causes fluorescence quenching. This allows monitoring of the reaction with SH-containing molecules by measurement of increases in fluorescence intensity and lifetime. Notably, the construct distributes into laterally ordered membrane domains of lipid vesicles, which is probably triggered by the length of its membrane anchor. The advantages of the new construct can be employed for several biological, biotechnological, and medicinal applications.
KW  - DBD dyes
KW  - fatty acids
KW  - liposomes
KW  - maleimide
KW  - membranes
KW  - palmitoylation
Y1  - 2018
U6  - https://doi.org/10.1002/cbic.201800268
SN  - 1439-4227
SN  - 1439-7633
VL  - 19
IS  - 15
SP  - 1643
EP  - 1647
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Shainyan, Bagrat A.
A1  - Suslova, Elena N.
A1  - Tran Dinh Phien, 
A1  - Shlykov, Sergey A.
A1  - Kleinpeter, Erich
T1  - Synthesis, conformational preferences in gas and solution, and molecular gear rotation in 1-(dimethylamino)-1-phenyl-1-silacyclohexane by gas phase electron diffraction (GED), LT NMR and theoretical calculations
JF  - Tetrahedron
N2  - 1-(Dimethylamino)-1-phenyl-1-silacyclohexane 1, was synthesized, and its molecular structure and conformational properties studied by gas-phase electron diffraction (GED), low temperature C-13 NMR spectroscopy and quantum-chemical calculations. The predominance of the 1-Ph-ax conformer (1-Ph-eq:1-Ph-ax ratio of 20:80%, Delta G degrees (317 K) = -0.87 kcal/mol) in the gas phase is close to the theoretically estimated conformational equilibrium. In solution, low temperature NMR spectroscopy showed analyzable decoalescence of C-ipso and C(1,5) carbon signals in C-13 NMR spectra at 103 K. Opposite to the gas state in the freon solution employed (CD2Cl2/CHFCl2/CHFCl2 = 1:1:3), which is still liquid at 100 K, the 1-Ph-eq conformer was found to be the preferred one [(1-Ph-eq: 1-Ph-ax = 77%: 23%, K = 77/23 = 2.8; -Delta G degrees = -RT In K (at 103 K) = 0.44 +/- 0.1 kcal/mol]. When comparing 1 with 1-phenyl-1-(X)silacylohexanes (X = H, Me, OMe, F, Cl), studied so far, the trend of predominance of the Ph-ax conformer in the gas phase and of the Ph-eq conformer in solution is confirmed.
KW  - 1-(Dimethylamino)-1-phenyl-1-silacyclohexane
KW  - Conformational analysis
KW  - Gas phase electron diffraction
KW  - Low-temperature d-NMR
KW  - DFT
KW  - MP2
KW  - M062X/6-311G** calculations
Y1  - 2018
U6  - https://doi.org/10.1016/j.tet.2018.06.023
SN  - 0040-4020
VL  - 74
IS  - 32
SP  - 4299
EP  - 4307
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Kretzschmar, Jerome
A1  - Haubitz, Toni
A1  - Huebner, Rene
A1  - Weiss, Stephan
A1  - Husar, Richard
A1  - Brendler, Vinzenz
A1  - Stumpf, Thorsten
T1  - Network-like arrangement of mixed-valence uranium oxide nanoparticles after glutathione-induced reduction of uranium(VI)
JF  - Chemical communications
N2  - Glutathione (GSH), a ubiquitous intracellular reducing tripeptide, is able to reduce hexavalent uranium, U(VI), to its tetravalent form, U(IV), in aqueous media in vitro, inducing the formation of nanocrystalline mixed-valence uranium oxide particles. After the initial reduction to U(V) and subsequent dismutation, the yielded U(IV) rapidly hydrolyses under near-neutral conditions forming 2-5 nm sized nanoparticles. The latter further aggregate to 20-40 nm chain-like building blocks that finally arrange as network-like structures.
Y1  - 2018
U6  - https://doi.org/10.1039/c8cc02070a
SN  - 1359-7345
SN  - 1364-548X
VL  - 54
IS  - 63
SP  - 8697
EP  - 8700
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Klopsch, Rebecca
A1  - Baldermann, Susanne
A1  - Voss, Alexander
A1  - Rohn, Sascha
A1  - Schreiner, Monika
A1  - Neugart, Susanne
T1  - Bread enriched with legume microgreens and leaves
BT  - ontogenetic and baking-driven changes in the profile of secondary plant metabolites
JF  - Frontiers in chemistry
N2  - Flavonoids, carotenoids, and chlorophylls were characterized in microgreens and leaves of pea (Pisum sativum) and lupin (Lupinus angustifolius) as these metabolites change during ontogeny. All metabolites were higher in the leaves for both species. Acylated quercetin and kaempferol sophorotrioses were predominant in pea. Genistein and malonylated chrysoeriol were predominant in lupin. Further, the impact of breadmaking on these metabolites using pea and lupin material of two ontogenetic stages as an added ingredient in wheat-based bread was assessed. In "pea microgreen bread" no decrease of quercetin was found with regard to the non-processed plant material. However kaempferol glycosides showed slight decreases induced by the breadmaking process in "pea microgreen bread" and "pea leaf bread." In "lupin microgreen bread" no decrease of genistein compared to the non-processed plant material was found. Chrysoeriol glycosides showed slight decreases induced by the breadmaking process in "lupin microgreen bread" and "lupin leaf bread." In all breads, carotenoids and chlorophylls were depleted however pheophytin formation was caused. Thus, pea and lupin microgreens and leaves are suitable, natural ingredients for enhancing health-promoting secondary plant metabolites in bread and may even be used to tailor bread for specific consumer health needs.
KW  - ontogeny
KW  - microgreen
KW  - pea
KW  - lupin
KW  - flavonoid
KW  - carotenoid
KW  - thermal processing of food
Y1  - 2018
U6  - https://doi.org/10.3389/fchem.2018.00322
SN  - 2296-2646
VL  - 6
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Fang, Liang
A1  - Gould, Oliver E. C.
A1  - Lysyakova, Liudmila
A1  - Jiang, Yi
A1  - Sauter, Tilman
A1  - Frank, Oliver
A1  - Becker, Tino
A1  - Schossig, Michael
A1  - Kratz, Karl
A1  - Lendlein, Andreas
T1  - Implementing and quantifying the shape-memory effect of single polymeric micro/nanowires with an atomic force microscope
JF  - ChemPhysChem : a European journal of chemical physics and physical chemistry
N2  - The implementation of shape-memory effects (SME) in polymeric micro- or nano-objects currently relies on the application of indirect macroscopic manipulation techniques, for example, stretchable molds or phantoms, to ensembles of small objects. Here, we introduce a method capable of the controlled manipulation and SME quantification of individual micro- and nano-objects in analogy to macroscopic thermomechanical test procedures. An atomic force microscope was utilized to address individual electro-spun poly(ether urethane) (PEU) micro- or nanowires freely suspended between two micropillars on a micro-structured silicon substrate. In this way, programming strains of 10 +/- 1% or 21 +/- 1% were realized, which could be successfully fixed. An almost complete restoration of the original free-suspended shape during heating confirmed the excellent shape-memory performance of the PEU wires. Apparent recovery stresses of sigma(max,app)=1.2 +/- 0.1 and 33.3 +/- 0.1MPa were obtained for a single microwire and nanowire, respectively. The universal AFM test platform described here enables the implementation and quantification of a thermomechanically induced function for individual polymeric micro- and nanosystems.
KW  - cyclic thermomechanical testing
KW  - atomic force microscopy
KW  - soft matter micro- and nanowires
KW  - shape-memory effect
KW  - materials science
Y1  - 2018
U6  - https://doi.org/10.1002/cphc.201701362
SN  - 1439-4235
SN  - 1439-7641
VL  - 19
IS  - 16
SP  - 2078
EP  - 2084
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - GEN
A1  - Dani, Alessandro
A1  - Taeuber, Karoline
A1  - Zhang, Weiyi
A1  - Schlaad, Helmut
A1  - Yuan, Jiayin
T1  - Stable covalently photo-cross-linked porous poly(ionic liquid) membrane with gradient pore size
T2  - Abstracts of papers : joint conference / The Chemical Institute of Cananda, CIC, American Chemical Society, ACS
N2  - Porous polyelectrolyte membranes stable in a highly ionic environment are obtained by covalent crosslinking of an imidazolium-based poly(ionic liquid). The crosslinking reaction involves the UV light-induced thiol-ene (click) chemistry, and the phase separation, occurring during the crosslinking step, generates a fully interconnected porous structure in the membrane. The porosity is on the order of the micrometer scale and the membrane shows a gradient of pore size across the membrane cross-section. The membrane can separate polystyrene latex particles of different size and undergoes actuation in contact with acetone due to the asymmetric porous structure.
Y1  - 2018
SN  - 0065-7727
VL  - 256
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Zhong, Qi
A1  - Mi, Lei
A1  - Metwalli, Ezzeldin
A1  - Biessmann, Lorenz
A1  - Philipp, Martine
A1  - Miasnikova, Anna
A1  - Laschewsky, Andre
A1  - Papadakis, Christine M.
A1  - Cubitt, Robert
A1  - Schwartzkopf, Matthias
A1  - Roth, Stephan V.
A1  - Wang, Jiping
A1  - Müller-Buschbaum, Peter
T1  - Effect of chain architecture on the swelling and thermal response of star-shaped thermo-responsive (poly(methoxy diethylene glycol acrylate)-block-polystyrene)(3) block copolymer films
JF  - Soft matter
N2  - The effect of chain architecture on the swelling and thermal response of thin films obtained from an amphiphilic three-arm star-shaped thermo-responsive block copolymer poly(methoxy diethylene glycol acrylate)-block-polystyrene ((PMDEGA-b-PS)(3)) is investigated by in situ neutron reflectivity (NR) measurements. The PMDEGA and PS blocks are micro-phase separated with randomly distributed PS nanodomains. The (PMDEGA-b-PS)(3) films show a transition temperature (TT) at 33 degrees C in white light interferometry. The swelling capability of the (PMDEGA-b-PS)(3) films in a D2O vapor atmosphere is better than that of films from linear PS-b-PMDEGA-b-PS triblock copolymers, which can be attributed to the hydrophilic end groups and limited size of the PS blocks in (PMDEGA-b-PS)(3). However, the swelling kinetics of the as-prepared (PMDEGA-b-PS)(3) films and the response of the swollen film to a temperature change above the TT are significantly slower than that in the PS-b-PMDEGA-b-PS films, which may be related to the conformation restriction by the star-shape. Unlike in the PS-b-PMDEGA-b-PS films, the amount of residual D2O in the collapsed (PMDEGA-b-PS)(3) films depends on the final temperature. It decreases from (9.7 +/- 0.3)% to (7.0 +/- 0.3)% or (6.0 +/- 0.3)% when the final temperatures are set to 35 degrees C, 45 degrees C and 50 degrees C, respectively. This temperature-dependent reduction of embedded D2O originates from the hindrance of chain conformation from the star-shaped chain architecture.
Y1  - 2018
U6  - https://doi.org/10.1039/c8sm00965a
SN  - 1744-683X
SN  - 1744-6848
VL  - 14
IS  - 31
SP  - 6582
EP  - 6594
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Tuncaboylu, Deniz Ceylan
A1  - Friess, Fabian
A1  - Wischke, Christian
A1  - Lendlein, Andreas
T1  - A multifunctional multimaterial system for on-demand protein release
JF  - Journal of controlled release
N2  - In order to provide best control of the regeneration process for each individual patient, the release of protein drugs administered during surgery may need to be timely adapted and/or delayed according to the progress of healing/regeneration. This study aims to establish a multifunctional implant system for a local on-demand release, which is applicable for various types of proteins. It was hypothesized that a tubular multimaterial container kit, which hosts the protein of interest as a solution or gel formulation, would enable on-demand release if equipped with the capacity of diameter reduction upon external stimulation. Using devices from poly(epsilon-caprolactone) networks, it could be demonstrated that a shape-memory effect activated by heat or NIR light enabled on-demand tube shrinkage. The decrease of diameter of these shape-memory tubes (SMT) allowed expelling the payload as demonstrated for several proteins including SDF-1 alpha, a therapeutically relevant chemotactic protein, to achieve e.g. continuous release with a triggered add-on dosing (open tube) or an on-demand onset of bolus or sustained release (sealed tube). Considering the clinical relevance of protein factors in (stem) cell attraction to lesions and the progress in monitoring biomarkers in body fluids, such on-demand release systems may be further explored e.g. in heart, nerve, or bone regeneration in the future.
KW  - Shape-memory polymer
KW  - On-demand release
KW  - Proteins
KW  - Poly(epsilon-caprolactone) networks
KW  - Near infrared light triggered shape-recovery
Y1  - 2018
U6  - https://doi.org/10.1016/j.jconrel.2018.06.022
SN  - 0168-3659
SN  - 1873-4995
VL  - 284
SP  - 240
EP  - 247
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Wang, Li
A1  - Razzaq, Muhammad Yasar
A1  - Rudolph, Tobias
A1  - Heuchel, Matthias
A1  - Nöchel, Ulrich
A1  - Mansfeld, Ulrich
A1  - Jiang, Yi
A1  - Gould, Oliver E. C.
A1  - Behl, Marc
A1  - Kratz, Karl
A1  - Lendlein, Andreas
T1  - Reprogrammable, magnetically controlled polymeric nanocomposite actuators
JF  - Material horizons
N2  - Soft robots and devices with the advanced capability to perform adaptive motions similar to that of human beings often have stimuli-sensitive polymeric materials as the key actuating component. The external signals triggering the smart polymers’ actuations can be transmitted either via a direct physical connection between actuator and controlling unit (tethered) or remotely without a connecting wire. However, the vast majority of such polymeric actuator materials are limited to one specific type of motion as their geometrical information is chemically fixed. Here, we present magnetically driven nanocomposite actuators, which can be reversibly reprogrammed to different actuation geometries by a solely physical procedure. Our approach is based on nanocomposite materials comprising spatially segregated crystallizable actuation and geometry determining units. Upon exposure to a specific magnetic field strength the actuators’ geometric memory is erased by the melting of the geometry determining units allowing the implementation of a new actuator shape. The actuation performance of the nanocomposites can be tuned and the technical significance was demonstrated in a multi-cyclic experiment with several hundreds of repetitive free-standing shape shifts without losing performance.
Y1  - 2018
U6  - https://doi.org/10.1039/c8mh00266e
SN  - 2051-6347
SN  - 2051-6355
VL  - 5
IS  - 5
SP  - 861
EP  - 867
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Yang, Guang
A1  - Hu, Rongting
A1  - Ding, Hong-ming
A1  - Kochovski, Zdravko
A1  - Mei, Shilin
A1  - Lu, Yan
A1  - Ma, Yu-qiang
A1  - Chen, Guosong
A1  - Jiang, Ming
T1  - CO2-switchable response of protein microtubules
BT  - behaviour and mechanism
JF  - Materials chemistry frontiers
N2  - Recently, we proposed a small molecular inducing ligand strategy to assemble proteins into highly-ordered structures via dual non-covalent interactions, i.e. carbohydrate-protein interaction and dimerization of Rhodamine B. Using this approach, artificial protein microtubules were successfully constructed. In this study, we find that these microtubules exhibit a perfect CO2 responsiveness; assembly and disassembly of these microtubules were nicely controlled by the alternative passage of CO2 and N-2. Upon the injection of CO2, a negative net-charged SBA turns into a neutral or positive net-charged SBA, which elongated, to some extent, the effective distance between SBA and Rhodamine B, resulting in the disassociation of the Rhodamine B dimer. Further experimental and simulation results reveal that the CO2-responsive mechanism differs from that of solubility change of the previously reported CO2-responsive synthetic materials.
Y1  - 2018
U6  - https://doi.org/10.1039/c8qm00245b
SN  - 2052-1537
VL  - 2
IS  - 9
SP  - 1642
EP  - 1646
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Hoang, Hoa T.
A1  - Haubitz, Toni
A1  - Kumke, Michael Uwe
T1  - Photophysics of "Floppy" Dyadsas Potential Biomembrane Probes
JF  - Journal of fluorescence
N2  - In the study a dyad (C6 probe), constructed of two dyes with highly different hydrophobicities, was investigated by steady-state and time-resolved spectroscopic techniques in chloroform, methanol, and in phospholipid vesicles, respectively. The dyad was built on two dyes: the lipophilic benzo[a]pyrene (BaP) and the hydrophilic sulforhodamine B (SRB). The dyes were linked via a short, but flexible alkyl chain (six C-atoms). Based on their spectroscopic properties, BaP and SRB showed a very efficient non-radiative resonance energy transfer in solution. Incorporation into a lipid bilayer limited the relative flexibility (degree of freedom) between donor and acceptor and was used for the investigation of fundamental photophysical aspects (especially of FRET) as well as to elucidate the potential of the dyad to probe the interface of vesicles (or cells). The location of the two dyes in vesicles and their respective accessibility for interactions with dye-specific antibodies was investigated. Based on the alteration of the anisotropy, on the rotational correlation time as well as on the diffusion coefficient the incorporation of the C6 probe into the vesicles was evaluated. Especially the limitation in the relative movements of the two dyes was considered and used to differentiate between potential parameters, that influence the energy transfer in the dyad. Transient absorption spectroscopy (TAS) and pulsed-interleave single molecule fluorescence experiments were performed to better understand the intramolecular interactions in the dyad. Finally, in a showcase for a biosensing application of the dyads, the binding of an SRB-specific antibody was investigated when the dyad was incorporated in vesicles.
KW  - Forster resonance energy transfer(FRET)
KW  - Antibody binding
KW  - Vesicles
KW  - Anisotropy
KW  - Fluorescence correlation
KW  - Single molecule fluorescence
KW  - Transient absorption
KW  - Pulsed interleaved excitation
Y1  - 2018
U6  - https://doi.org/10.1007/s10895-018-2286-4
SN  - 1053-0509
SN  - 1573-4994
VL  - 28
IS  - 5
SP  - 1225
EP  - 1237
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Schulze, Sven
A1  - Wehrhold, Michel
A1  - Hille, Carsten
T1  - Femtosecond-Pulsed laser written and etched fiber bragg gratings for fiber-optical biosensing
JF  - Sensors
N2  - We present the development of a label-free, highly sensitive fiber-optical biosensor for online detection and quantification of biomolecules. Here, the advantages of etched fiber Bragg gratings (eFBG) were used, since they induce a narrowband Bragg wavelength peak in the reflection operation mode. The gratings were fabricated point-by-point via a nonlinear absorption process of a highly focused femtosecond-pulsed laser, without the need of prior coating removal or specific fiber doping. The sensitivity of the Bragg wavelength peak to the surrounding refractive index (SRI), as needed for biochemical sensing, was realized by fiber cladding removal using hydrofluoric acid etching. For evaluation of biosensing capabilities, eFBG fibers were biofunctionalized with a single-stranded DNA aptamer specific for binding the C-reactive protein (CRP). Thus, the CRP-sensitive eFBG fiber-optical biosensor showed a very low limit of detection of 0.82 pg/L, with a dynamic range of CRP detection from approximately 0.8 pg/L to 1.2 mu g/L. The biosensor showed a high specificity to CRP even in the presence of interfering substances. These results suggest that the proposed biosensor is capable for quantification of CRP from trace amounts of clinical samples. In addition, the adaption of this eFBG fiber-optical biosensor for detection of other relevant analytes can be easily realized.
KW  - fiber Bragg gratings
KW  - ultra-fast laser inscription
KW  - fiber etching
KW  - nanostructure fabrication
KW  - fiber-optical sensors
KW  - aptamers
KW  - C-reactive protein
KW  - biomarker
Y1  - 2018
U6  - https://doi.org/10.3390/s18092844
SN  - 1424-8220
VL  - 18
IS  - 9
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Pereira, Rui F. P.
A1  - Zehbe, Kerstin
A1  - Günter, Christina
A1  - dos Santos, Tiago
A1  - Nunes, Silvia C.
A1  - Almeida Paz, Filipe A.
A1  - Silva, Maria M.
A1  - Granja, Pedro L.
A1  - Taubert, Andreas
A1  - de Zea Bermudez, Verónica
T1  - Ionic liquid-assisted synthesis of mesoporous silk fibroin/silica hybrids for biomedical applications
JF  - ACS Omega
N2  - New mesoporous silk fibroin (SF)/silica hybrids were processed via a one-pot soft and energy-efficient sol-gel chemistry and self-assembly from a silica precursor, an acidic or basic catalyst, and the ionic liquid 1-butyl-3-methylimidazolium chloride, acting as both solvent and mesoporosity-inducer. The as-prepared materials were obtained as slightly transparent-opaque, amorphous monoliths, easily transformed into powders, and stable up to ca. 300 degrees C. Structural data suggest the formation of a hexagonal mesostructure with low range order and apparent surface areas, pore volumes, and pore radii of 205-263 m(2) g(-1), 0.16-0.19 cm(3) g(-1), and 1.2-1.6 nm, respectively. In all samples, the dominating conformation of the SF chains is the beta-sheet. Cytotoxicity/bioactivity resazurin assays and fluorescence microscopy demonstrate the high viability of MC3T3 pre-osteoblasts to indirect (>= 99 +/- 9%) and direct (78 +/- 2 to 99 +/- 13%) contact with the SF/silica materials. Considering their properties and further improvements, these systems are promising candidates to be explored in bone tissue engineering. They also offer excellent prospects as electrolytes for solid-state electrochemical devices, in particular for fuel cells.
Y1  - 2018
U6  - https://doi.org/10.1021/acsomega.8b02051
SN  - 2470-1343
VL  - 3
IS  - 9
SP  - 10811
EP  - 10822
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Haubitz, Toni
A1  - Tsushima, Satoru
A1  - Steudtner, Robin
A1  - Drobot, Björn
A1  - Geipel, Gerhard
A1  - Stumpf, Thorsten
A1  - Kumke, Michael Uwe
T1  - Ultrafast Transient Absorption Spectroscopy of UO(2)(2+)and [UO2Cl](+)
JF  - The journal of physical chemistry : A, Molecules, spectroscopy, kinetics, environment & general theory
N2  - For the only water coordinated "free" uranyl (VI) aquo ion in perchlorate solution we identified and assigned several different excited states and showed that the (3)Delta state is the luminescent triplet state from transient absorption spectroscopy. With additional data from other spectroscopic methods (TRLFS, UV/vis) we generated a detailed Jablonski diagram and determined rate constants for several state transitions, like the inner conversion rate constant from the (3)Phi state to the (3)Delta state transition to be 0.35 ps(-1). In contrast to luminescence measurements, it was possible to observe the highly quenched uranyl(VI) ion in highly concentrated chloride solution by TAS and we were able to propose a dynamic quenching mechanism, where chloride complexation is followed by the charge transfer from the excited state uranyl(VI) to chloride. This proposed quenching route is supported by TD-DFT calculations.
Y1  - 2018
U6  - https://doi.org/10.1021/acs.jpca.8b05567
SN  - 1089-5639
VL  - 122
IS  - 35
SP  - 6970
EP  - 6977
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Senf, Deborah
A1  - Ruprecht, Colin
A1  - Kishani, Saina
A1  - Matic, Aleksandar
A1  - Toriz, Guillermo
A1  - Gatenholm, Paul
A1  - Wagberg, Lars
A1  - Pfrengle, Fabian
T1  - Tailormade polysaccharides with defined branching patterns
BT  - Enzymatic polymerization of arabinoxylan oligosaccharides
JF  - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition
N2  - The heterogeneous nature of non-cellulosic polysaccharides, such as arabinoxylan, makes it difficult to correlate molecular structure with macroscopic properties. To study the impact of specific structural features of the polysaccharides on crystallinity or affinity to other cell wall components, collections of polysaccharides with defined repeating units are required. Herein, a chemoenzymatic approach to artificial arabinoxylan polysaccharides with systematically altered branching patterns is described. The polysaccharides were obtained by glycosynthase-catalyzed polymerization of glycosyl fluorides derived from arabinoxylan oligosaccharides. X-ray diffraction and adsorption experiments on cellulosic surfaces revealed that the physicochemical properties of the synthetic polysaccharides strongly depend on the specific nature of their substitution patterns. The artificial polysaccharides allow structure-property relationship studies that are not accessible by other means.
KW  - carbohydrates
KW  - enzymes
KW  - glycosynthases
KW  - structure elucidation
KW  - synthetic methods
Y1  - 2018
U6  - https://doi.org/10.1002/anie.201806871
SN  - 1433-7851
SN  - 1521-3773
VL  - 57
IS  - 37
SP  - 11987
EP  - 11992
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Uchida, Ryusuke
A1  - Binet, Silvia
A1  - Arora, Neha
A1  - Jacopin, Gwenole
A1  - Alotaibi, Mohammad Hayal
A1  - Taubert, Andreas
A1  - Zakeeruddin, Shaik Mohammed
A1  - Dar, M. Ibrahim
A1  - Graetzel, Michael
T1  - Insights about the Absence of Rb Cation from the 3D Perovskite Lattice
BT  - Effect on the Structural, Morphological, and Photophysical Properties and Photovoltaic Performance
JF  - Small
N2  - Efficiencies >20% are obtained from the perovskite solar cells (PSCs) employing Cs+ and Rb+ based perovskite compositions; therefore, it is important to understand the effect of these inorganic cations specifically Rb+ on the properties of perovskite structures. Here the influence of Cs+ and Rb+ is elucidated on the structural, morphological, and photophysical properties of perovskite structures and the photovoltaic performances of resulting PSCs. Structural, photoluminescence (PL), and external quantum efficiency studies establish the incorporation of Cs+ (x < 10%) but amply rule out the possibility of Rb-incorporation into the MAPbI(3) (MA = CH3NH3+) lattice. Moreover, morphological studies and time-resolved PL show that both Cs+ and Rb+ detrimentally affect the surface coverage of MAPbI(3) layers and charge-carrier dynamics, respectively, by influencing nucleation density and by inducing nonradiative recombination. In addition, differential scanning calorimetry shows that the transition from orthorhombic to tetragonal phase occurring around 160 K requires more thermal energy for the Cs-containing MAPbI(3) systems compared to the pristine MAPbI(3). Investigation including mixed halide (I/Br) and mixed cation A-cation based compositions further confirms the absence of Rb+ from the 3D-perovskite lattice. The fundamental insights gained through this work will be of great significance to further understand highly promising perovskite compositions.
KW  - cation miscibility
KW  - cesium cation
KW  - perovskite solar cells
KW  - rubidium cation
KW  - X-ray diffraction
Y1  - 2018
U6  - https://doi.org/10.1002/smll.201802033
SN  - 1613-6810
SN  - 1613-6829
VL  - 14
IS  - 36
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Vacogne, Charlotte Dominique
A1  - Wei, Chunxiang
A1  - Tauer, Klaus
A1  - Schlaad, Helmut
T1  - Self-assembly of alpha-helical polypeptides into microscopic and enantiomorphic spirals
JF  - Journal of the american chemical society
N2  - Helical structures are ubiquitous in biological materials and often serve a structural purpose. Bioinspired helical materials can be challenging to synthesize and rarely reach the degree of hierarchy of their natural counterparts. Here we report the first example of particles synthesized by direct emulsification of polypeptides found to display spiral morphologies in the dry state. The polypeptides were alpha-helical homo- and copolypeptides of gamma-benzyl glutamate and allylglycine. The chirality of the spirals was controlled by the chirality of the alpha-helices. Notably, right-handed alpha-helical polypeptides (rich in 1, residues) produced clockwise spirals, whereas left-handed alpha-helical polypeptides (rich in D residues) produced the enantiomorphs, i.e., counterclockwise spirals. The disruption of the alpha-helical conformation by the introduction of chiral defects led to less regular spirals and in some cases their suppression. A hypothesis for the transmission of helicity and chirality from a molecular to a higher hierarchical level, involving fibril bundling of coiled alpha-helices, is proposed.
Y1  - 2018
U6  - https://doi.org/10.1021/jacs.8b06503
SN  - 0002-7863
VL  - 140
IS  - 36
SP  - 11387
EP  - 11394
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Tan, Li
A1  - Liu, Bing
A1  - Siemensmeyer, Konrad
A1  - Glebe, Ulrich
A1  - Böker, Alexander
T1  - Synthesis of thermo-responsive nanocomposites of superparamagnetic cobalt nanoparticlesipoly(N-isopropylacrylamide)
JF  - Journal of colloid and interface science
N2  - Novel nanocomposites of superparamagnetic cobalt nanoparticles (Co NPs) and poly(N-isopropylacrylamide) (PNIPAM) were fabricated through surface-initiated atom-transfer radical polymerization (SI-ATRP). We firstly synthesized a functional ATRP initiator, containing an amine (as anchoring group) and a 2-bromopropionate group (SI-ATRP initiator). Oleic acid- and trioctylphosphine oxide-coated Co NPs were then modified with the initiator via ligand exchange. The process is facile and rapid for efficient surface functionalization and afterwards the Co NPs can be dispersed into polar solvent DMF without aggregation. Transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and dynamic light scattering measurements confirmed the success of ligand exchange. The following polymerization of NIPAM was conducted on the surface of Co NPs. Temperature-dependent dynamic light scattering study showed the responsive behavior of PNIPAM-coated Co NPs. The combination of superparamagnetic and thermo-responsive properties in these hybrid nanoparticles is promising for future applications e.g. in biomedicine. (C) 2018 Elsevier Inc. All rights reserved.
KW  - Nanoparticles
KW  - Superparamagnetic
KW  - Surface-initiated atom-transfer radical
KW  - polymerization
KW  - Responsivity
Y1  - 2018
U6  - https://doi.org/10.1016/j.jcis.2018.04.074
SN  - 0021-9797
SN  - 1095-7103
VL  - 526
SP  - 124
EP  - 134
PB  - Elsevier
CY  - San Diego
ER  -