TY  - JOUR
A1  - Morgner, Frank
A1  - Lecointre, Alexandre
A1  - Charbonniere, Loic J.
A1  - Löhmannsröben, Hans-Gerd
T1  - Detecting free hemoglobin in blood plasma and serum with luminescent terbium complexes
JF  - Physical chemistry, chemical physics : a journal of European Chemical Societies
N2  - Hemolysis, the rupturing of red blood cells, can result from numerous medical conditions (in vivo) or occur after collecting blood specimen or extracting plasma and serum out of whole blood (in vitro). In clinical laboratory practice, hemolysis can be a serious problem due to its potential to bias detection of various analytes or biomarkers. Here we present the first "mix-and-measure' method to assess the degree of hemolysis in biosamples using luminescence spectroscopy. Luminescent terbium complexes (LTC) were studied in the presence of free hemoglobin (Hb) as indicators for hemolysis in TRIS-buffer, and in fresh human plasma with absorption, excitation and emission measurements. Our findings indicate dynamic as well as resonance energy transfer (FRET) between the LTC and the porphyrin ligand of hemoglobin. This transfer leads to a decrease in luminescence intensity and decay time even at nanomolar hemoglobin concentrations either in buffer or plasma. Luminescent terbium complexes are very sensitive to free hemoglobin in buffer and blood plasma. Due to the instant change in luminescence properties of the LTC in presence of Hb it is possible to access the concentration of hemoglobin via spectroscopic methods without incubation time or further treatment of the sample thus enabling a rapid and sensitive detection of hemolysis in clinical diagnostics.
Y1  - 2015
U6  - https://doi.org/10.1039/c4cp04206a
SN  - 1463-9076
SN  - 1463-9084
VL  - 17
IS  - 3
SP  - 1740
EP  - 1745
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Cramer, Ashley D.
A1  - Gambinossi, Filippo
A1  - Wischerhoff, Erik
A1  - Laschewsky, André
A1  - Miller, Reinhard
A1  - Ferri, James K.
T1  - Flexible thermoresponsive nanomembranes at the aqueous-air interface
JF  - Chemical communications
N2  - A synthetic pathway is described to construct thermoresponsive freestanding nanomembranes at the aqueous-air interface of a pendant drop. Dynamic control of the reaction kinetics allows formation of viscoelastic interfaces supporting anisotropic stresses and mechanical stability, which can be tuned by external stimuli.
Y1  - 2015
U6  - https://doi.org/10.1039/c4cc07359b
SN  - 1359-7345
SN  - 1364-548X
VL  - 51
IS  - 5
SP  - 877
EP  - 880
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Tritschler, U.
A1  - Beck, F.
A1  - Schlaad, Helmut
A1  - Cölfen, Helmut
T1  - Electrochromic properties of self-organized multifunctional V2O5-polymer hybrid films
JF  - Journal of materials chemistry : C, Materials for optical and electronic devices
N2  - Bio-inspired V2O5-polymer hybrid films were prepared following a one-step self-organization procedure based on liquid crystal formation of organic and inorganic components. These materials were previously reported to exhibit advantageous mechanical properties, comparable to biomaterials, such as human bone and dentin. Here, we show that these hybrid films prepared via a fast and simple synthesis procedure have an additional function as an electrochromic material, exhibiting a long-term cycle stability under alternating potentials. The structures were found to remain intact without visible changes after more than hundred switching cycles and storing the devices for several weeks. Consequently, this multifunctional V2O5-polymer hybrid system shows great promise for various technical applications.
Y1  - 2015
U6  - https://doi.org/10.1039/c4tc02138j
SN  - 2050-7526
SN  - 2050-7534
VL  - 3
IS  - 5
SP  - 950
EP  - 954
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Secker, Christian
A1  - Robinson, Joshua W.
A1  - Schlaad, Helmut
T1  - Alkyne-X modification of polypeptoids
JF  - European polymer journal
N2  - Poly(N-propargyl glycine) (PNPG) can be readily prepared by ring-opening polymerization of N-propargyl glycine N-carboxyanhydride (NCA) and modified using various addition reactions such as copper catalyzed [3+2] cycloaddition of azide, radical (photo-)addition of thiol, nucleophilic addition of ethylene oxide, and thermal induced cross-linking. It is demonstrated that PNPG can serve as a modular platform to produce a bibliography of novel functional polypeptoid or pseudopeptide materials, including polypeptoid ionic liquids and graft copolymers.
KW  - Polypeptoid
KW  - NCA
KW  - Post-polymerization modification
KW  - Click chemistry
Y1  - 2015
U6  - https://doi.org/10.1016/j.eurpolymj.2014.08.028
SN  - 0014-3057
SN  - 1873-1945
VL  - 62
SP  - 394
EP  - 399
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Nöchel, Ulrich
A1  - Reddy, Chaganti Srinivasa
A1  - Wang, Ke
A1  - Cui, Jing
A1  - Zizak, Ivo
A1  - Behl, Marc
A1  - Kratz, Karl
A1  - Lendlein, Andreas
T1  - Nanostructural changes in crystallizable controlling units determine the temperature-memory of polymers
JF  - Journal of materials chemistry : A, Materials for energy and sustainability
N2  - Temperature-memory polymers remember the temperature, where they were deformed recently, enabled by broad thermal transitions. In this study, we explored a series of crosslinked poly[ethylene-co-(vinyl acetate)] networks (cPEVAs) comprising crystallizable polyethylene (PE) controlling units exhibiting a pronounced temperature-memory effect (TME) between 16 and 99 degrees C related to a broad melting transition (similar to 100 degrees C). The nanostructural changes in such cPEVAs during programming and activation of the TME were analyzed via in situ X-ray scattering and specific annealing experiments. Different contributions to the mechanism of memorizing high or low deformation temperatures (T-deform) were observed in cPEVA, which can be associated to the average PE crystal sizes. At high deformation temperatures (>50 degrees C), newly formed PE crystals, which are established during cooling when fixing the temporary shape, dominated the TME mechanism. In contrast, at low T-deform (<50 degrees C), corresponding to a cold drawing scenario, the deformation led preferably to a disruption of existing large crystals into smaller ones, which then fix the temporary shape upon cooling. The observed mechanism of memorizing a deformation temperature might enable the prediction of the TME behavior and the knowledge based design of other TMPs with crystallizable controlling units.
Y1  - 2015
U6  - https://doi.org/10.1039/c4ta06586g
SN  - 2050-7488
SN  - 2050-7496
VL  - 3
IS  - 16
SP  - 8284
EP  - 8293
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Mondal, Suvendu Sekhar
A1  - Behrens, Karsten
A1  - Matthes, Philipp R.
A1  - Schönfeld, Fabian
A1  - Nitsch, Jörn
A1  - Steffen, Andreas
A1  - Primus, Philipp-Alexander
A1  - Kumke, Michael Uwe
A1  - Müller-Buschbaum, Klaus
A1  - Holdt, Hans-Jürgen
T1  - White light emission of IFP-1 by in situ co-doping of the MOF pore system with Eu3+ and Tb3+
JF  - Journal of materials chemistry : C, Materials for optical and electronic devices
Y1  - 2015
U6  - https://doi.org/10.1039/c4tc02919d
SN  - 2050-7526
SN  - 2050-7534
VL  - 3
IS  - 18
SP  - 4623
EP  - 4631
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Matis, Jochen Rene
A1  - Schoenborn, Jan Boyke
A1  - Saalfrank, Peter
T1  - A multi-reference study of the byproduct formation for a ring-closed dithienylethene photoswitch
JF  - Physical chemistry, chemical physics : a journal of European Chemical Societies
N2  - Photodriven molecular switches are sometimes hindered in their performance by forming byproducts which act as dead ends in sequences of switching cycles, leading to rapid fatigue effects. Understanding the reaction pathways to unwanted byproducts is a prerequisite for preventing them. This article presents a study of the photochemical reaction pathways for byproduct formation in the photochromic switch 1,2-bis-(3-thienyl)-ethene. Specifically, using single-and multi-reference methods the post-deexcitation reaction towards the byproduct in the electronic ground state S-0 when starting from the S-1-S-0 conical intersection (CoIn), is considered in detail. We find an unusual low-energy pathway, which offers the possibility for the formation of a dyotropic byproduct. Several high-energy pathways can be excluded with high probability.
Y1  - 2015
U6  - https://doi.org/10.1039/c5cp00987a
SN  - 1463-9076
SN  - 1463-9084
VL  - 17
IS  - 21
SP  - 14088
EP  - 14095
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Mirskova, Anna N.
A1  - Adamovich, Sergey N.
A1  - Mirskov, Rudolf G.
A1  - Kolesnikova, Olga P.
A1  - Schilde, Uwe
T1  - Immunoactive ionic liquids based on 2-hydroxyethylamines and 1-R-indol-3-ylsulfanylacetic acids. Crystal and molecular structure of immunodepressant tris-(2-hydroxyethyl)ammonium indol-3-ylsulfanylacetate
JF  - Open chemistry : formerly Central European journal of chemistry
N2  - Immunoactive ionic liquids (2-hydroxyethyl) ammonium 1-R-indol-3-ylsulfanyl-acetates HN+R1R2(CH2CH2OH)center dot O-(O)CCH2S-Ind-R-3-1(1-5), were synthesized by the reaction of (2-hydroxyethyl)amines with indol-3-ylsulfanylacetic- or 1-benzylindol-3-ylsulfanylacetic acid. 1: R-1 = R-2 = CH2CH2OH, R-3 = H; 2: R-1 =CH3, R-2=CH2CH2OH, R3 = H; 3: R-1 = R-2 = CH3, R-3 = H; 4: R-1 = R-2 = CH2CH2OH, R-3 = CH2C6H5; 5: R-1 = CH3; R-2 = CH2CH2OH; R-3 = CH2C6H5. The structure of each compound was elucidated by IR, NMR H-1, C-13, and N-15 techniques and their composition was confirmed by elemental analysis. The crystal structure of tris-(2-hydroxyethyl) ammonium indol-3-ylsulfanylacetate was investigated by X-ray diffraction analysis. Immunoactive properties of the title compounds were screened.
KW  - Protic 2-hydroxyethylammonium ionic liquids
KW  - 2-Hydroxyethylammonium 1-R-indol-3-ylsulfanylacetates
KW  - Crystal and molecular structure
KW  - Immunoactive properties
Y1  - 2015
U6  - https://doi.org/10.1515/chem-2015-0018
SN  - 2391-5420
VL  - 13
IS  - 1
SP  - 149
EP  - 155
PB  - De Gruyter Open
CY  - Warsaw
ER  - 
TY  - JOUR
A1  - Vacogne, Charlotte D.
A1  - Brosnan, Sarah M.
A1  - Masic, Admir
A1  - Schlaad, Helmut
T1  - Fibrillar gels via the self-assembly of poly(L-glutamate)-based statistical copolymers
JF  - Polymer Chemistry
N2  - Polypeptides having secondary structures often undergo self-assembly which can extend over multiple length scales. Poly(gamma-benzyl-L-glutamate) (PBLG), for example, folds into a-helices and forms physical organogels, whereas poly(L-glutamic acid) (PLGA at acidic pH) or poly(L-glutamate) (PLG at neutral/basic pH) do not form hydrogels. We explored the gelation of modified PBLG and investigated the deprotection of the carboxylic acid moieties in such gels to yield unique hydrogels. This was accomplished through photo-crosslinking gelation of poly(gamma-benzyl-L-glutamate-co-allylglycine) statistical copolymers in toluene, tetrahydrofuran, and 1,4-dioxane. Unlike most polymer-based chemical gels, our gels were prepared from dilute solutions (<20 g L-1, i.e., <2% w/v) of low molar mass polymers. Despite such low concentrations and molar masses, our dioxane gels showed high mechanical stability and little shrinkage; remarkably, they also exhibited a porous fibrillar network. Deprotection of the carboxylic acid moieties in dioxane gels yielded pH responsive and highly absorbent PLGA/PLG-based hydrogels (swelling ratio of up to 87), while preserving the network structure, which is an unprecedented feature in the context of crosslinked PLGA gels. These outstanding properties are highly attractive for biomedical materials.
Y1  - 2015
U6  - https://doi.org/10.1039/c5py00491h
SN  - 1759-9954
SN  - 1759-9962
VL  - 6
IS  - 28
SP  - 5040
EP  - 5052
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Schulze, Michael
A1  - Utecht, Manuel Martin
A1  - Moldt, Thomas
A1  - Przyrembel, Daniel
A1  - Gahl, Cornelius
A1  - Weinelt, Martin
A1  - Saalfrank, Peter
A1  - Tegeder, Petra
T1  - Nonlinear optical response of photochromic azobenzene-functionalized self-assembled monolayers
JF  - Physical chemistry, chemical physics : a journal of European Chemical Societies
N2  - The combination of photochromic and nonlinear optical (NLO) properties of azobenzene-functionalized self-assembled monolayers (SAMs) constitutes an intriguing step towards novel photonic and optoelectronic devices. By utilizing the second-order NLO process of second harmonic generation (SHG), supported by density-functional theory and correlated wave function method calculations, we demonstrate that the photochromic interface provides the necessary prerequisites en route towards possible future technical applications: we find a high NLO contrast on the order of 16% between the switching states. These are furthermore accessible reversibly and with high efficiencies in terms of cross sections on the order of 10(-18) cm(2) for both photoisomerization reactions, i.e., drivable by means of low-power LED light sources. Finally, both photostationary states (PSSs) are thermally stable at ambient conditions.
Y1  - 2015
U6  - https://doi.org/10.1039/c5cp03093e
SN  - 1463-9076
SN  - 1463-9084
VL  - 17
IS  - 27
SP  - 18079
EP  - 18086
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Wu, Lei
A1  - Glebe, Ulrich
A1  - Böker, Alexander
T1  - Surface-initiated controlled radical polymerizations from silica nanoparticles, gold nanocrystals, and bionanoparticles
JF  - Polymer Chemistry
N2  - In recent years, core/shell nanohybrids containing a nanoparticle core and a distinct surrounding shell of polymer brushes have received extensive attention in nanoelectronics, nanophotonics, catalysis, nanopatterning, drug delivery, biosensing, and many others. From the large variety of existing polymerization methods on the one hand and strategies for grafting onto nanoparticle surfaces on the other hand, the combination of grafting-from with controlled radical polymerization (CRP) techniques has turned out to be the best suited for synthesizing these well-defined core/shell nanohybrids and is known as surface-initiated CRP. Most common among these are surface-initiated atom transfer radical polymerization (ATRP), surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization, and surface-initiated nitroxide-mediated polymerization (NMP). This review highlights the state of the art of growing polymers from nanoparticles using surface-initiated CRP techniques. We focus on mechanistic aspects, synthetic procedures, and the formation of complex architectures as well as novel properties. From the vast number of examples of nanoparticle/polymer hybrids formed by surface-initiated CRP techniques, we present nanohybrid formation from the particularly important and most studied silica nanoparticles, gold nanocrystals, and proteins which can be regarded as bionanoparticles.
Y1  - 2015
U6  - https://doi.org/10.1039/c5py00525f
SN  - 1759-9954
SN  - 1759-9962
VL  - 6
IS  - 29
SP  - 5143
EP  - 5184
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Banerjee, Shiladitya
A1  - Stueker, Tony
A1  - Saalfrank, Peter
T1  - Vibrationally resolved optical spectra of modified diamondoids obtained from time-dependent correlation function methods
JF  - Physical chemistry, chemical physics : a journal of European Chemical Societies
N2  - Optical properties of modified diamondoids have been studied theoretically using vibrationally resolved electronic absorption, emission and resonance Raman spectra. A time-dependent correlation function approach has been used for electronic two-state models, comprising a ground state (g) and a bright, excited state (e), the latter determined from linear-response, time-dependent density functional theory (TD-DFT). The harmonic and Condon approximations were adopted. In most cases origin shifts, frequency alteration and Duschinsky rotation in excited states were considered. For other cases where no excited state geometry optimization and normal mode analysis were possible or desired, a short-time approximation was used. The optical properties and spectra have been computed for (i) a set of recently synthesized sp(2)/sp(3) hybrid species with CQC double-bond connected saturated diamondoid subunits, (ii) functionalized (mostly by thiol or thione groups) diamondoids and (iii) urotropine and other C-substituted diamondoids. The ultimate goal is to tailor optical and electronic features of diamondoids by electronic blending, functionalization and substitution, based on a molecular-level understanding of the ongoing photophysics.
Y1  - 2015
U6  - https://doi.org/10.1039/c5cp02615f
SN  - 1463-9076
SN  - 1463-9084
VL  - 17
IS  - 29
SP  - 19656
EP  - 19669
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Kroener, Dominik
T1  - Laser-driven electron dynamics for circular dichroism in mass spectrometry: from onephoton excitations to multiphoton ionization
JF  - Physical chemistry, chemical physics : a journal of European Chemical Societies
N2  - The distinction of enantiomers is a key aspect of chemical analysis. In mass spectrometry the distinction of enantiomers has been achieved by ionizing the sample with circularly polarized laser pulses and comparing the ion yields for light of opposite handedness. While resonant excitation conditions are expected to be most efficient, they are not required for the detection of a circular dichroism (CD) in the ion yield. However, the prediction of the size and sign of the circular dichroism becomes challenging if non-resonant multiphoton excitations are used to ionize the sample. Employing femtosecond laser pulses to drive electron wavepacket dynamics based on ab initio calculations, we attempt to reveal underlying mechanisms that determine the CD under non-resonant excitation conditions. Simulations were done for (R)-1,2-propylene oxide, using time-dependent configuration interaction singles with perturbative doubles (TD-CIS(D)) and the aug-cc-pVTZ basis set. Interactions between the electric field and the electric dipole and quadrupole as well as between the magnetic field and the magnetic dipole were explicitly accounted for. The ion yield was determined by treating states above the ionization potential as either stationary or non-stationary with energy-dependent lifetimes based on an approved heuristic approach. The observed population dynamics do not allow for a simple interpretation, because of highly non-linear interactions. Still, the various transition pathways are governed by resonant enantiospecific n-photon excitation, with preferably high transition dipole moments, which eventually dominate the CD in the ionized population.
Y1  - 2015
U6  - https://doi.org/10.1039/c5cp02193f
SN  - 1463-9076
SN  - 1463-9084
VL  - 17
IS  - 29
SP  - 19643
EP  - 19655
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Kirchhecker, Sarah
A1  - Tröger-Müller, Steffen
A1  - Bake, Sebastian
A1  - Antonietti, Markus
A1  - Taubert, Andreas
A1  - Esposito, Davide
T1  - Renewable pyridinium ionic liquids from the continuous hydrothermal decarboxylation of furfural-amino acid derived pyridinium zwitterions
JF  - Green chemistry : an international journal and green chemistry resource
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 counter-ions. 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  - 17
IS  - 8
SP  - 4151
EP  - 4156
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Strauch, Peter
A1  - Neumann, Mike
A1  - Kelling, Alexandra
A1  - Schilde, Uwe
T1  - Bis(1,2-dithiosquarato)nickelates(II): Synthesis, Structure, EPR and Thermal Behavior
JF  - Acta chimica Slovenica
N2  - 1,2-Dithiosquaratonickelates are available by direct synthesis from metal salts with dipotassium-1,2-dithiosquarate and the appropriate counter cations. The synthesis and characterization, including mass spectrometry, of a series 1,2-dithiosquaratonickelates(II), [Ni(dtsq)(2)](2-), with several "onium" cations is reported and the X-ray structures of two diamagnetic complexes, (HexPh(3)P)(2)[Ni(dtsq)(2)] and (BuPh3P)(2)[Ni(dtsq)(2)] with sterically demanding counter ions are presented. The diamagnetic nickel complexes have been doped as host lattices with traces of Cu(II) to measure EPR for additional structural information. The thermal behavior of this series is studied by thermogravimetry and differential thermal analysis (TG/DTA). The thermolysis in air as well as under nitrogen atmosphere of these complexes results in nickel oxide nano-particles in all cases, which are characterized by X-ray powder diffraction.
KW  - 1,2-Dithiosquarate,1,2-Dithiosquaratonickelate
KW  - X-ray structure
KW  - TG/DTA
KW  - Nickel oxide
KW  - EPR spectroscopy
Y1  - 2015
SN  - 1318-0207
SN  - 1580-3155
VL  - 62
IS  - 2
SP  - 288
EP  - 296
PB  - Drustvo
CY  - Ljubljana
ER  - 
TY  - JOUR
A1  - Klier, Dennis Tobias
A1  - Kumke, Michael Uwe
T1  - Upconversion NaYF4:Yb:Er nanoparticles co-doped with Gd3+ and Nd3+ for thermometry on the nanoscale
JF  - RSC Advances
N2  - In the present work, the upconversion luminescence properties of oleic acid capped NaYF4:Gd3+:Yb3+:Er3+ upconversion nanoparticles (UCNP) with pure beta crystal phase and Nd3+ ions as an additional sensitizer were studied in the temperature range of 288 K < T < 328 K. The results of this study showed that the complex interplay of different mechanisms and effects, causing the special temperature behavior of the UCNP can be developed into thermometry on the nanoscale, e.g. to be applied in biological systems on a cellular level. The performance was improved by the use of Nd3+ as an additional dopant utilizing the cascade sensitization mechanism in tri-doped UCNP.
Y1  - 2015
U6  - https://doi.org/10.1039/c5ra11502g
SN  - 2046-2069
VL  - 5
IS  - 82
SP  - 67149
EP  - 67156
PB  - Royal Society of Chemistry
CY  - Cambridge
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  - 
TY  - JOUR
A1  - Vacogne, Charlotte D.
A1  - Schlaad, Helmut
T1  - Primary ammonium/tertiary amine-mediated controlled ring opening polymerisation of amino acid N-carboxyanhydrides
JF  - Chemical communications
N2  - Stable commercial primary ammonium chlorides were combined with tertiary amines to initiate the controlled ring opening polymerisation of amino acid N-carboxyanhydrides to yield polypeptides with defined end group structure, predetermined molar mass and narrow molar mass distribution.
Y1  - 2015
U6  - https://doi.org/10.1039/c5cc06905j
SN  - 1359-7345
SN  - 1364-548X
VL  - 51
IS  - 86
SP  - 15645
EP  - 15648
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Klier, Dennis Tobias
A1  - Kumke, Michael Uwe
T1  - Analysing the effect of the crystal structure on upconversion luminescence in Yb3+, Er3+-co-doped NaYF4 nanomaterials
JF  - Journal of materials chemistry : C, Materials for optical and electronic devices
N2  - NaYF4:Yb:Er nanoparticles (UCNP) were synthesized under mild experimental conditions to obtain a pure cubic lattice. Upon annealing at different temperatures up to T-an = 700 degrees C phase transitions to the hexagonal phase and back to the cubic phase were induced. The UCNP materials obtained for different T-an were characterized with respect to the lattice phase using standard XRD and Raman spectroscopy as well as steady state and time resolved upconversion luminescence. The standard techniques showed that for the annealing temperature range 300 degrees C < T-an < 600 degrees C the hexagonal lattice phase was dominant. For T-an < 300 degrees C hardly any change in the lattice phase could be deduced, whereas for T-an > 600 degrees C a back transfer to the alpha-phase was observed. Complementarily, the luminescence upconversion properties of the annealed UCNP materials were characterized in steady state and time resolved luminescence measurements. Distinct differences in the upconversion luminescence intensity, the spectral intensity distribution and the luminescence decay kinetics were found for the cubic and hexagonal lattice phases, respectively, corroborating the results of the standard analytical techniques used. In laser power dependent measurements of the upconversion luminescence intensity it was found that the green (G1, G2) and red (R) emission of Er3+ showed different effects of T-an on the number of required photons reflecting the differences in the population routes of different energy levels involved. Furthermore, the intensity ratio of G(full)/R is highly effected by the laser power only when the beta-phase is present, whereas the G1/G2 intensity ratio is only slightly effected regardless of the crystal phase. Moreover, based on different upconversion luminescence kinetics characteristics of the cubic and hexagonal phase time-resolved area normalized emission spectra (TRANES) proved to be a very sensitive tool to monitor the phase transition between cubic and hexagonal phases. Based on the TRANES analysis it was possible to resolve the lattice phase transition in more detail for 200 degrees C < T-an < 300 degrees C, which was not possible with the standard techniques.
Y1  - 2015
U6  - https://doi.org/10.1039/c5tc02218e
SN  - 2050-7526
SN  - 2050-7534
VL  - 3
IS  - 42
SP  - 11228
EP  - 11238
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Roch, Toralf
A1  - Kratz, Karl
A1  - Ma, Nan
A1  - Lendlein, Andreas
T1  - Polymeric inserts differing in their chemical composition as substrates for dendritic cell cultivation
JF  - Clinical hemorheology and microcirculation : blood flow and vessels
N2  - Dendritic cells (DC) contribute to immunity by presenting antigens to T cells and shape the immune response by the secretion of cytokines. Due to their immune stimulatory potential DC-based therapies are promising approaches to overcome tolerance e.g. against tumors. In order to enforce the immunogenicity of DCs, they have to be matured and activated in vitro, which requires an appropriate cell culture substrate, supporting their survival expansion and activation.
 Since most cell culture devices are not optimized for DC growth, it is hypothesized that polymers with certain physicochemical properties can positively influence the DC cultures. With the aim to evaluate the effects that polymers with different chemical compositions have on the survival, the activation status, and the cytokine/chemokine secretion profile of DC, their interaction with polystyrene (PS), polycarbonate (PC), poly(ether imide) (PEI), and poly(styrene-co-acrylonitrile) (PSAN)-based cell culture inserts was investigated. By using this insert system, which fits exactly into 24 well cell culture plates, effects induced from the culture dish material can be excluded. The viability of untreated DC after incubation with the different inserts was not influenced by the different inserts, whereas LPS-activatedDCshowed an increased survival after cultivation on PC, PS, and PSAN compared to tissue culture polystyrene (TCP). The activation status of DC estimated by the expression of CD40, CD80, CD83, CD86 and HLA-DR expression was not altered by the different inserts in untreated DC but slightly reduced when LPS-activated DC were cultivated on PC, PS, PSAN, and PEI compared to TCP. For each polymeric cell culture insert a distinct cytokine profile could be observed.
 Since inserts with different chemical compositions of the inserts did not substantially alter the behavior of DC all insert systems could be considered as alternative substrate. The observed increased survival on some polymers, which showed in contrast to TCP a hydrophobic surface, could be beneficial for certain applications such as T cell expansion and activation.
KW  - Biomaterials
KW  - dendritic cells
KW  - cell culture device
KW  - amorphous polymers
Y1  - 2015
U6  - https://doi.org/10.3233/CH-152004
SN  - 1386-0291
SN  - 1875-8622
VL  - 61
IS  - 2
SP  - 347
EP  - 357
PB  - IOS Press
CY  - Amsterdam
ER  -