TY  - JOUR
A1  - Stefancu, Andrei
A1  - Nan, Lin
A1  - Zhu, Li
A1  - Chis, Vasile
A1  - Bald, Ilko
A1  - Liu, Min
A1  - Leopold, Nicolae
A1  - Maier, Stefan A.
A1  - Cortes, Emiliano
T1  - Controlling plasmonic chemistry pathways through specific ion effects
JF  - Advanced optical materials
N2  - Plasmon-driven dehalogenation of brominated purines has been recently explored as a model system to understand fundamental aspects of plasmon-assisted chemical reactions. Here, it is shown that divalent Ca2+ ions strongly bridge the adsorption of bromoadenine (Br-Ade) to Ag surfaces. 
Such ion-mediated binding increases the molecule's adsorption energy leading to an overlap of the metal energy states and the molecular states, enabling the chemical interface damping (CID) of the plasmon modes of the Ag nanostructures (i.e., direct electron transfer from the metal to Br-Ade). 
Consequently, the conversion of Br-Ade to adenine almost doubles following the addition of Ca2+. 
These experimental results, supported by theoretical calculations of the local density of states of the Ag/Br-Ade complex, indicate a change of the charge transfer pathway driving the dehalogenation reaction, from Landau damping (in the lack of Ca2+ ions) to CID (after the addition of Ca2+). 
The results show that the surface dynamics of chemical species (including water molecules) play an essential role in charge transfer at plasmonic interfaces and cannot be ignored. It is envisioned that these results will help in designing more efficient nanoreactors, harnessing the full potential of plasmon-assisted chemistry.
KW  - chemical interface damping
KW  - Hofmeister effect
KW  - hydration layer
KW  - plasmonic chemistry
KW  - specific ion effects
KW  - surface-enhanced Raman scattering
Y1  - 2022
U6  - https://doi.org/10.1002/adom.202200397
SN  - 2195-1071
VL  - 10
IS  - 14
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Banerji, Amitabh
A1  - Thyssen, Christoph
A1  - Pampel, Barbara
A1  - Huwer, Johannes
T1  - Naturwissenschaftsunterricht und Informatik
BT  - bringt zusammen, was zusammen gehört?!
BT  - bringing together, what belongs together?!
JF  - Chemie konkret : CHEMKON ; Forum für Unterricht und Didaktik
N2  - Computer literacy plays an increasingly important role in the education of 21st-century society. For chemistry' education. this results in two aspects: On the one hand. informatics education concepts can help to promote chemistry- and science-specific ways of thinking and working. On the other hand, chemistry education can contribute to information education. This paper addresses both aspects and tries to point out the Mutual benefits of informatics education and science education with regards to chemistry lessons.
N2  - Informatische Bildung spielt eine immer zentralere Rolle in der Bildung einer Gesellschaft des 21. Jahrhunderts. Für den Chemieunterricht ergeben sich daraus zwei Aspekte: Einerseits können Konzepte der informatischen Bildung dabei helfen, chemie- und naturwissenschaftsspezifische Denk- und Arbeitsweisen zu fördern. Andererseits kann der Chemieunterricht einen Beitrag für die informatische Bildung leisten. Dieser Artikel geht auf beide Aspekte ein und versucht die gegenseitigen Vorteile der informatischen Bildung und der naturwissenschaftlichen Bildung im Chemieunterricht darzustellen.
T2  - Science education and computer literacy
KW  - computer literacy
KW  - scientific literacy
KW  - informatische Bildung
KW  - naturwissenschaftliche Bildung
Y1  - 2021
U6  - https://doi.org/10.1002/ckon.202100008
SN  - 0944-5846
SN  - 1521-3730
VL  - 28
IS  - 6
SP  - 263
EP  - 265
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Zhao, Yuhang
A1  - Opitz, Andreas
A1  - Eljarrat, Alberto
A1  - Kochovski, Zdravko
A1  - Koch, Christoph
A1  - Koch, Norbert
A1  - Lu, Yan
T1  - Kinetic study on the adsorption of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane on Ag nanoparticles in chloroform
BT  - implications for the charge transfer complex of Ag-F(4)TCNQ
JF  - ACS applied nano materials
N2  - In this study, the kinetics of the adsorption of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F(4)TCNQ) on the surface of Ag nanoparticles (Ag NPs) in chloroform has been intensively investigated, as molecular doping is known to play a crucial role in organic electronic devices. Based on the results obtained from UV-visible (vis)-near-infrared (NIR) absorption spectroscopy, cryogenic transmission electron microscopy, scanning nanobeam electron diffraction, and electron energy loss spectroscopy, a two-step interaction kinetics has been proposed for the Ag NPs and F(4)TCNQ molecules, which includes the first step of electron transfer from Ag NPs to F(4)TCNQ indicated by the ionization of F(4)TCNQ and the second step of the formation of a Ag-F(4)TCNQ complex. The whole process has been followed via UV-vis-NIR absorption spectroscopy, which reveals distinct kinetics at two stages: the instantaneous ionization and the long-term complex formation. The kinetics and the influence of the molar ratio of Ag NPs/F(4)TCNQ molecules on the interaction between Ag NPs and F(4)TCNQ molecules in an organic solution are reported herein for the first time. Furthermore, the control experiment with silica-coated Ag NPs manifests that the charge transfer at the surface between Ag NPs and F(4)TCNQ molecules is prohibited by a silica layer of 18 nm.
KW  - Ag nanoparticles
KW  - F(4)TCNQ
KW  - phase transfer
KW  - kinetics
KW  - electron transfer
KW  - surface interaction
Y1  - 2021
U6  - https://doi.org/10.1021/acsanm.1c02153
SN  - 2574-0970
VL  - 4
IS  - 11
SP  - 11625
EP  - 11635
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Zhou, Shuo
A1  - Xu, Xun
A1  - Ma, Nan
A1  - Jung, Friedrich
A1  - Lendlein, Andreas
T1  - Influence of sterilization conditions on sulfate-functionalized polyGGE
JF  - Clinical hemorheology and microcirculation : blood flow and vessels
N2  - Sulfated biomolecules are known to influence numerous biological processes in all living organisms. Particularly, they contribute to prevent and inhibit the hypercoagulation condition. The failure of polymeric implants and blood contacting devices is often related to hypercoagulation and microbial contamination. Here, bioactive sulfated biomacromolecules are mimicked by sulfation of poly(glycerol glycidyl ether) (polyGGE) films. Autoclaving, gamma-ray irradiation and ethylene oxide (EtO) gas sterilization techniques were applied to functionalized materials. The sulfate group density and hydrophilicity of sulfated polymers were decreased while chain mobility and thermal degradation were enhanced post autoclaving when compared to those after EtO sterilization. These results suggest that a quality control after sterilization is mandatory to ensure the amount and functionality of functionalized groups are retained.
KW  - Sulfated polymer
KW  - sulfation
KW  - sterilization
KW  - ethylene oxide
Y1  - 2021
U6  - https://doi.org/10.3233/CH-211241
SN  - 1386-0291
SN  - 1875-8622
VL  - 79
IS  - 4
SP  - 597
EP  - 608
PB  - IOS Press
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Michaelis, Vivien
A1  - Aengenheister, Leonie
A1  - Tuchtenhagen, Max
A1  - Rinklebe, Jörg
A1  - Ebert, Franziska
A1  - Schwerdtle, Tanja
A1  - Buerki-Thurnherr, Tina
A1  - Bornhorst, Julia
T1  - Differences and interactions in placental manganese and iron transfer across an in vitro model of human villous trophoblasts
JF  - International journal of molecular sciences
N2  - Manganese (Mn) as well as iron (Fe) are essential trace elements (TE) important for the maintenance of physiological functions including fetal development. However, in the case of Mn, evidence suggests that excess levels of intrauterine Mn are associated with adverse pregnancy outcomes. Although Mn is known to cross the placenta, the fundamentals of Mn transfer kinetics and mechanisms are largely unknown. Moreover, exposure to combinations of TEs should be considered in mechanistic transfer studies, in particular for TEs expected to share similar transfer pathways. Here, we performed a mechanistic in vitro study on the placental transfer of Mn across a BeWo b30 trophoblast layer. Our data revealed distinct differences in the placental transfer of Mn and Fe. While placental permeability to Fe showed a clear inverse dose-dependency, Mn transfer was largely independent of the applied doses. Concurrent exposure of Mn and Fe revealed transfer interactions of Fe and Mn, indicating that they share common transfer mechanisms. In general, mRNA and protein expression of discussed transporters like DMT1, TfR, or FPN were only marginally altered in BeWo cells despite the different exposure scenarios highlighting that Mn transfer across the trophoblast layer likely involves a combination of active and passive transport processes.
KW  - manganese
KW  - iron
KW  - placental transfer
KW  - TE interactions
KW  - BeWo b30
KW  - trophoblasts
Y1  - 2022
U6  - https://doi.org/10.3390/ijms23063296
SN  - 1422-0067
VL  - 23
IS  - 6
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Crovetto, Andrea
A1  - Kojda, Danny
A1  - Yi, Feng
A1  - Heinselman, Karen N.
A1  - LaVan, David A.
A1  - Habicht, Klaus
A1  - Unold, Thomas
A1  - Zakutayev, Andriy
T1  - Crystallize It before It diffuses
BT  - kinetic stabilization of thin-film phosphorus-rich semiconductor CuP2
JF  - Journal of the american chemical society
N2  - Numerous phosphorus-rich metal phosphides containing both P-P bonds and metal-P bonds are known from the solid-state chemistry literature. A method to grow these materials in thin-film form would be desirable, as thin films are required in many applications and they are an ideal platform for high-throughput studies. In addition, the high density and smooth surfaces achievable in thin films are a significant advantage for characterization of transport and optical properties. Despite these benefits, there is hardly any published work on even the simplest binary phosphorus-rich phosphide films. Here, we demonstrate growth of single-phase CuP2 films by a two-step process involving reactive sputtering of amorphous CuP2+x and rapid annealing in an inert atmosphere. At the crystallization temperature, CuP2 is thermodynamically unstable with respect to Cu3P and P-4. However, CuP2 can be stabilized if the amorphous precursors are mixed on the atomic scale and are sufficiently close to the desired composition (neither too P poor nor too P rich). Fast formation of polycrystalline CuP2, combined with a short annealing time, makes it possible to bypass the diffusion processes responsible for decomposition. We find that thin-film CuP2 is a 1.5 eV band gap semiconductor with interesting properties, such as a high optical absorption coefficient (above 10(5) cm(-1)), low thermal conductivity (1.1 W/(K m)), and composition-insensitive electrical conductivity (around 1 S/cm). We anticipate that our processing route can be extended to other phosphorus-rich phosphides that are still awaiting thin-film synthesis and will lead to a more complete understanding of these materials and of their potential applications.
Y1  - 2022
U6  - https://doi.org/10.1021/jacs.2c04868
SN  - 0002-7863
SN  - 1520-5126
VL  - 144
IS  - 29
SP  - 13334
EP  - 13343
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Tung, Wing Tai
A1  - Maring, Janita A.
A1  - Xu, Xun
A1  - Liu, Yue
A1  - Becker, Matthias
A1  - Somesh, Dipthi Bachamanda
A1  - Klose, Kristin
A1  - Wang, Weiwei
A1  - Sun, Xianlei
A1  - Ullah, Imran
A1  - Kratz, Karl
A1  - Neffe, Axel T.
A1  - Stamm, Christof
A1  - Ma, Nan
A1  - Lendlein, Andreas
T1  - In vivo performance of a cell and factor free multifunctional fiber mesh modulating postinfarct myocardial remodeling
JF  - Advanced Functional Materials
N2  - Guidance of postinfarct myocardial remodeling processes by an epicardial patch system may alleviate the consequences of ischemic heart disease. As macrophages are highly relevant in balancing immune response and regenerative processes their suitable instruction would ensure therapeutic success. A polymeric mesh capable of attracting and instructing monocytes by purely physical cues and accelerating implant degradation at the cell/implant interface is designed. In a murine model for myocardial infarction the meshes are compared to those either coated with extracellular matrix or loaded with induced cardiomyocyte progenitor cells. All implants promote macrophage infiltration and polarization in the epicardium, which is verified by in vitro experiments. 6 weeks post-MI, especially the implantation of the mesh attenuates left ventricular adverse remodeling processes as shown by reduced infarct size (14.7% vs 28-32%) and increased wall thickness (854 mu m vs 400-600 mu m), enhanced angiogenesis/arteriogenesis (more than 50% increase compared to controls and other groups), and improved heart function (ejection fraction = 36.8% compared to 12.7-31.3%). Upscaling as well as process controls is comprehensively considered in the presented mesh fabrication scheme to warrant further progression from bench to bedside.
KW  - bioinstructive materials
KW  - cardiac regeneration
KW  - function by structure;
KW  - modulation of in vivo regeneration
KW  - multifunctional biomaterials
Y1  - 2022
U6  - https://doi.org/10.1002/adfm.202110179
SN  - 1616-301X
SN  - 1616-3028
VL  - 32
IS  - 31
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Breternitz, Joachim
A1  - Schorr, Susan
T1  - Symmetry relations in wurtzite nitrides and oxide nitrides and the curious case of Pmc2(1)
JF  - Acta crystallographica / International Union of Crystallography. Section A, Foundations and advances
N2  - Binary III-V nitrides such as AlN, GaN and InN in the wurtzite-type structure have long been considered as potent semiconducting materials because of their optoelectronic properties, amongst others. With rising concerns over the utilization of scarce elements, a replacement of the trivalent cations by others in ternary and multinary nitrides has led to the development of different variants of nitrides and oxide nitrides crystallizing in lower-symmetry variants of wurtzite. This work presents the symmetry relationships between these structural types specific to nitrides and oxide nitrides and updates some prior work on this matter. The non-existence of compounds crystallizing in Pmc2(1), formally the highest subgroup of the wurtzite type fulfilling Pauling's rules for 1:1:2 stoichiometries, has been puzzling scientists for a while; a rationalization is given, from a crystallographic basis, of why this space group is unlikely to be adopted.
KW  - group-subgroup relationships
KW  - nitride materials
KW  - wurtzite type
Y1  - 2021
U6  - https://doi.org/10.1107/S2053273320015971
SN  - 2053-2733
VL  - 77
IS  - 3
SP  - 208
EP  - 216
PB  - Blackwell
CY  - Oxford [u.a.]
ER  - 
TY  - JOUR
A1  - Mei, Shilin
A1  - Siebert, Andreas
A1  - Xu, Yaolin
A1  - Quan, Ting
A1  - Garcia-Diez, Raul
A1  - Bär, Marcus
A1  - Härtel, Paul
A1  - Abendroth, Thomas
A1  - Dörfler, Susanne
A1  - Kaskel, Stefan
A1  - Lu, Yan
T1  - Large-Scale Synthesis of Nanostructured Carbon-Ti4O7 Hollow Particles as Efficient Sulfur Host Materials for Multilayer Lithium-Sulfur Pouch Cells
JF  - Batteries & supercaps
N2  - Applications of advanced cathode materials with well-designed chemical components and/or optimized nanostructures promoting the sulfur redox kinetics and suppressing the shuttle effect of polysulfides are highly valued. However, in the case of actual lithium-sulfur (Li-S) batteries under practical working conditions, one long-term obstacle still exists, which is mainly due to the difficulties in massive synthesis of such nanomaterials with low cost and ease of control on the nanostructure. Herein, we develop a facile synthesis of carbon coated Ti4O7 hollow nanoparticles (Ti4O7) using spherical polymer electrolyte brush as soft template, which is scalable via utilizing a minipilot reactor. The C Ti4O7 hollow nanoparticles provide strong chemical adsorption to polysulfides through the large polar surface and additional physical confinement by rich micro- & mesopores and have successfully been employed as an efficient sulfur host for multilayer pouch cells. Besides, the sluggish kinetics of the sulfur and lithium sulfide redox mechanism can be improved by the highly conductive Ti4O7 via catalyzation of the conversion of polysulfides. Consequently, the C-Ti4O7 based pouch cell endows a high discharge capacity of 1003 mAhg(-1) at 0.05 C, a high-capacity retention of 83.7% after 100 cycles at 0.1 C, and a high Coulombic efficiency of 97.5% at the 100th cycle. This work proposes an effective approach to transfer the synthesis of hollow Ti4O7 nanoparticles from lab- to large-scale production, paving the way to explore a wide range of advanced nanomaterials for multilayer Li-S pouch cells.
KW  - lithium-sulfur batteries
KW  - pouch cell
KW  - spherical polyelectrolyte brushes (SPB)
KW  - Ti4O7
Y1  - 2022
U6  - https://doi.org/10.1002/batt.202100398
SN  - 2566-6223
VL  - 5
IS  - 6
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Lepre, Enrico
A1  - Heske, Julian
A1  - Nowakowski, Michal
A1  - Scoppola, Ernesto
A1  - Zizak, Ivo
A1  - Heil, Tobias
A1  - Kühne, Thomas D.
A1  - Antonietti, Markus
A1  - Lopez-Salas, Nieves
A1  - Albero, Josep
T1  - Ni-based electrocatalysts for unconventional CO2 reduction reaction to formic acid
JF  - Nano energy
N2  - Electrochemical reduction stands as an alternative to revalorize CO2. Among the different alternatives, Ni single atoms supported on carbonaceous materials are an appealing catalytic solution due to the low cost and versatility of the support and the optimal usage of Ni and its predicted selectivity and efficiency (ca. 100% towards CO). Herein, we have used noble carbonaceous support derived from cytosine to load Ni subnanometric sites. The large heteroatom content of the support allows the stabilization of up to 11 wt% of Ni without the formation of nanoparticles through a simple impregnation plus calcination approach, where nickel promotes the stabilization of C3NOx frameworks and the oxidative support promotes a high oxidation state of nickel. EXAFS analysis points at nickel single atoms or subnanometric clusters coordinated by oxygen in the material surface. Unlike the wellknown N-coordinated Ni single sites selectivity towards CO2 reduction, O-coordinated-Ni single sites (ca. 7 wt% of Ni) reduced CO2 to CO, but subnanometric clusters (11 wt% of Ni) foster the unprecedented formation of HCOOH with 27% Faradaic efficiency at - 1.4 V. Larger Ni amounts ended up on the formation of NiO nanoparticles and almost 100% selectivity towards hydrogen evolution.
KW  - CO 2 reduction reaction
KW  - Noble carbon
KW  - Ni-O4 electrocatalysts
KW  - Formic acid
Y1  - 2022
U6  - https://doi.org/10.1016/j.nanoen.2022.107191
SN  - 2211-2855
SN  - 2211-3282
VL  - 97
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Haubitz, Toni
A1  - Drobot, Björn
A1  - Tsushima, Satoru
A1  - Steudtner, Robin
A1  - Stumpf, Thorsten
A1  - Kumke, Michael Uwe
T1  - Quenching mechanism of uranyl(VI) by chloride and bromide in aqueous and non-aqueous solutions
JF  - The journal of physical chemistry : A, Molecules, spectroscopy, kinetics, environment & general theory
N2  - A major hindrance in utilizing uranyl(VI) luminescence as a standard analytical tool, for example, in environmental monitoring or nuclear industries, is quenching by other ions such as halide ions, which are present in many relevant matrices of uranyl(VI) speciation. Here, we demonstrate through a combination of time-resolved laser-induced fluorescence spectroscopy, transient absorption spectroscopy, and quantum chemistry that coordinating solvent molecules play a crucial role in U(VI) halide luminescence quenching. We show that our previously suggested quenching mechanism based on an internal redox reaction of the 1:2-uranyl-halide-complex holds also true for bromide-induced quenching of uranyl(VI). By adopting specific organic solvents, we were able to suppress the separation of the oxidized halide ligand X-2(center dot-) and the formed uranyl(V) into fully solvated ions, thereby "reigniting" U(VI) luminescence. Time-dependent density functional theory calculations show that quenching occurs through the outer-sphere complex of U(VI) and halide in water, while the ligand-to-metal charge transfer is strongly reduced in acetonitrile.
Y1  - 2021
U6  - https://doi.org/10.1021/acs.jpca.1c02487
SN  - 1089-5639
SN  - 1520-5215
VL  - 125
IS  - 20
SP  - 4380
EP  - 4389
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Pham, Duong Tung
A1  - Quan, Ting
A1  - Mei, Shilin
A1  - Lu, Yan
T1  - Colloidal metal sulfide nanoparticles for high performance electrochemical energy storage systems
JF  - Current opinion in green and sustainable chemistry
N2  - Transition metal sulfides have emerged as excellent replacement candidates of traditional insertion electrode materials based on their conversion or alloying mechanisms, facilitating high specific capacity and rate ability. However, parasitic reactions such as massive volume change during the discharge/ charge processes, intermediate polysulfide dissolution, and passivating solid electrolyte interface formation have led to poor cyclability, hindering their feasibility and applicability in energy storage systems. Colloidal metal sulfide nanoparticles, a special class that integrates the intrinsic chemical properties of metal sulfides and their specified structural features, have fairly enlarged their contribution due to the synergistic effect. This review highlights the latest synthetic approaches based on colloidal process. Their corresponding electrochemical outcomes will also be discussed, which are thoroughly updated along with their insight scientific standpoints.
Y1  - 2022
U6  - https://doi.org/10.1016/j.cogsc.2022.100596
SN  - 2452-2236
VL  - 34
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Reitenbach, Julija
A1  - Geiger, Christina
A1  - Wang, Peixi
A1  - Vagias, Apostolos N.
A1  - Cubitt, Robert
A1  - Schanzenbach, Dirk
A1  - Laschewsky, André
A1  - Papadakis, Christine M.
A1  - Müller-Buschbaum, Peter
T1  - Effect of magnesium salts with chaotropic anions on the swelling behavior of PNIPMAM thin films
JF  - Macromolecules : a publication of the American Chemical Society
N2  - Poly(N-isopropylmethacrylamide) (PNIPMAM) is a stimuli responsive polymer, which in thin film geometry exhibits a volume-phase transition upon temperature increase in water vapor. The swelling behavior of PNIPMAM thin films containing magnesium salts in water vapor is investigated in view of their potential application as nanodevices. Both the extent and the kinetics of the swelling ratio as well as the water content are probed with in situ time-of-flight neutron reflectometry. Additionally, in situ Fourier-transform infrared (FTIR) spectroscopy provides information about the local solvation of the specific functional groups, while two-dimensional FTIR correlation analysis further elucidates the temporal sequence of solvation events. The addition of Mg(ClO4)2 or Mg(NO3)2 enhances the sensitivity of the polymer and therefore the responsiveness of switches and sensors based on PNIPMAM thin films. It is found that Mg(NO3)2 leads to a higher relative water uptake and therefore achieves the highest thickness gain in the swollen state.
Y1  - 2023
U6  - https://doi.org/10.1021/acs.macromol.2c02282
SN  - 0024-9297
SN  - 1520-5835
VL  - 56
IS  - 2
SP  - 567
EP  - 577
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Nchiozem-Ngnitedem, Vaderament-Alexe
A1  - Sperlich, Eric
A1  - Matieta, Valaire Yemene
A1  - Kuete, Jenifer Reine Ngnouzouba
A1  - Kuete, Victor
A1  - Omer, Ejlal A. A.
A1  - Efferth, Thomas
A1  - Schmidt, Bernd
T1  - Synthesis and bioactivity of isoflavones from ficus carica and some non-natural analogues
JF  - Journal of natural products : Lloydia
N2  - FicucariconeD (1) and its 4 '-demethyl congener 2 are isoflavones isolated from fruits of Ficus carica that share a 5,7-dimethoxy-6-prenyl-substituted A-ring. Both naturalproducts were, for the first time, obtained by chemical synthesisin six steps, starting from 2,4,6-trihydroxyacetophenone. Key stepsare a microwave-promoted tandem sequence of Claisen- and Cope-rearrangementsto install the 6-prenyl substituent and a Suzuki-Miyaura crosscoupling for installing the B-ring. By using various boronic acids,non-natural analogues become conveniently available. All compoundswere tested for cytotoxicity against drug-sensitive and drug-resistanthuman leukemia cell lines, but were found to be inactive. The compoundswere also tested for antimicrobial activities against a panel of eightGram-negative and two Gram-positive bacterial strains. Addition ofthe efflux pump inhibitor phenylalanine-arginine-beta-naphthylamide(PA beta N) significantly improved the antibiotic activity in mostcases, with MIC values as low as 2.5 mu M and activity improvementfactors as high as 128-fold.
KW  - Antimicrobial activity
KW  - Bacteria
KW  - Ethers
KW  - Flavonoids
KW  - Mixtures
Y1  - 2023
U6  - https://doi.org/10.1021/acs.jnatprod.3c00219
SN  - 0163-3864
SN  - 1520-6025
VL  - 86
IS  - 6
SP  - 1520
EP  - 1528
PB  - American Chemical Society
CY  - Washington, DC
ER  - 
TY  - JOUR
A1  - Geiger, Christina
A1  - Reitenbach, Julija
A1  - Henschel, Cristiane
A1  - Kreuzer, Lucas
A1  - Widmann, Tobias
A1  - Wang, Peixi
A1  - Mangiapia, Gaetano
A1  - Moulin, Jean-François
A1  - Papadakis, Christine M.
A1  - Laschewsky, André
A1  - Müller-Buschbaum, Peter
T1  - Ternary nanoswitches realized with multiresponsive PMMA-b-PNIPMAM films in mixed water/acetone vapor atmospheres
JF  - Advanced engineering materials
N2  - To systematically add functionality to nanoscale polymer switches, an understanding of their responsive behavior is crucial. Herein, solvent vapor stimuli are applied to thin films of a diblock copolymer consisting of a short poly(methyl methacrylate) (PMMA) block and a long poly(N-isopropylmethacrylamide) (PNIPMAM) block for realizing ternary nanoswitches. Three significantly distinct film states are successfully implemented by the combination of amphiphilicity and co-nonsolvency effect. The exposure of the thin films to nitrogen, pure water vapor, and mixed water/acetone (90 vol%/10 vol%) vapor switches the films from a dried to a hydrated (solvated and swollen) and a water/acetone-exchanged (solvated and contracted) equilibrium state. These three states have distinctly different film thicknesses and solvent contents, which act as switch positions "off," "on," and "standby." For understanding the switching process, time-of-flight neutron reflectometry (ToF-NR) and spectral reflectance (SR) studies of the swelling and dehydration process are complemented by information on the local solvation of functional groups probed with Fourier-transform infrared (FTIR) spectroscopy. An accelerated responsive behavior beyond a minimum hydration/solvation level is attributed to the fast build-up and depletion of the hydration shell of PNIPMAM, caused by its hydrophobic moieties promoting a cooperative hydration character.
KW  - co-nonsolvency
KW  - diblock copolymers
KW  - nanoswitches
KW  - neutron reflectometry
KW  - thin films
Y1  - 2021
U6  - https://doi.org/10.1002/adem.202100191
SN  - 1438-1656
SN  - 1527-2648
VL  - 23
IS  - 11
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Melani, Giacomo
A1  - Nagata, Yuki
A1  - Saalfrank, Peter
T1  - Vibrational energy relaxation of interfacial OH on a water-covered alpha-Al2O3(0001) surface
BT  - a non-equilibrium ab initio molecular dynamics study
JF  - Physical chemistry, chemical physics : PCCP ; a journal of European chemical societies
N2  - Vibrational relaxation of adsorbates is a sensitive tool to probe energy transfer at gas/solid and liquid/solid interfaces. The most direct way to study relaxation dynamics uses time-resolved spectroscopy. Here we report on a non-equilibrium ab initio molecular dynamics (NE-AIMD) methodology to model vibrational relaxation of OH vibrations on a hydroxylated, water-covered alpha-Al2O3(0001) surface. In our NE-AIMD approach, after exciting selected O-H bonds their coupling to surface phonons and to the water adlayer is analyzed in detail, by following both the energy flow in time, as well as the time-evolution of Vibrational Density of States (VDOS) curves. The latter are obtained from Time-dependent Correlation Functions (TCFs) and serve as prototypical, generic representatives of time-resolved vibrational spectra. As most important results, (i) we find a few-picosecond lifetime of the excited modes and (ii) identify both hydrogen-bonded aluminols and water molecules in the adsorbed water layer as main dissipative channels, while the direct coupling to Al2O3 surface phonons is of minor importance on the timescales of interest. Our NE-AIMD/TCF methodology is powerful for complex adsorbate systems, in principle even reacting ones, and opens a way towards time-resolved vibrational spectroscopy.
Y1  - 2021
U6  - https://doi.org/10.1039/d0cp03777j
SN  - 1463-9076
SN  - 1463-9084
VL  - 23
IS  - 13
SP  - 7714
EP  - 7723
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Wang, Zhenyu
A1  - Fritsch, Daniel
A1  - Berendts, Stefan
A1  - Lerch, Martin
A1  - Breternitz, Joachim
A1  - Schorr, Susan
T1  - Elucidation of the reaction mechanism for the synthesis of ZnGeN2 through Zn2GeO4 ammonolysis
JF  - Chemical science / RSC, Royal Society of Chemistry
N2  - Ternary II-IV-N-2 materials have been considered as a promising class of materials that combine photovoltaic performance with earth-abundance and low toxicity. When switching from binary III-V materials to ternary II-IV-N-2 materials, further structural complexity is added to the system that may influence its optoelectronic properties. Herein, we present a systematic study of the reaction of Zn2GeO4 with NH3 that produces zinc germanium oxide nitrides, and ultimately approach stoichiometric ZnGeN2, using a combination of chemical analyses, X-ray powder diffraction and DFT calculations. Elucidating the reaction mechanism as being dominated by Zn and O extrusion at the later reaction stages, we give an insight into studying structure-property relationships in this emerging class of materials.
Y1  - 2021
U6  - https://doi.org/10.1039/d1sc00328c
SN  - 2041-6539
VL  - 12
IS  - 24
SP  - 8493
EP  - 8500
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Saeedi Garakani, Sadaf
A1  - Xie, Dongjiu
A1  - Khorsand Kheirabad, Atefeh
A1  - Lu, Yan
A1  - Yuan, Jiayin
T1  - Template-synthesis of a poly(ionic liquid)-derived Fe1-xS/nitrogen-doped porous carbon membrane and its electrode application in lithium-sulfur batteries
JF  - Materials advances
N2  - This study deals with the facile synthesis of Fe1-xS nanoparticle-containing nitrogen-doped porous carbon membranes (denoted as Fe1-xS/N-PCMs) via vacuum carbonization of hybrid porous poly(ionic liquid) (PIL) membranes, and their successful use as a sulfur host material to mitigate the shuttle effect in lithium-sulfur (Li-S) batteries. The hybrid porous PIL membranes as the sacrificial template were prepared via ionic crosslinking of a cationic PIL with base-neutralized 1,1 '-ferrocenedicarboxylic acid, so that the iron source was molecularly incorporated into the template. The carbonization process was investigated in detail at different temperatures, and the chemical and porous structures of the carbon products were comprehensively analyzed. The Fe1-xS/N-PCMs prepared at 900 degrees C have a multimodal pore size distribution with a satisfactorily high surface area and well-dispersed iron sulfide nanoparticles to physically and chemically confine the LiPSs. The sulfur/Fe1-xS/N-PCM composites were then tested as electrodes in Li-S batteries, showing much improved capacity, rate performance and cycle stability, in comparison to iron sulfide-free, nitrogen-doped porous carbon membranes.
Y1  - 2021
U6  - https://doi.org/10.1039/d1ma00441g
SN  - 2633-5409
VL  - 2
IS  - 15
SP  - 5203
EP  - 5212
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Xu, Xun
A1  - Nie, Yan
A1  - Wang, Weiwei
A1  - Ma, Nan
A1  - Lendlein, Andreas
T1  - Periodic thermomechanical modulation of toll-like receptor expression and distribution in mesenchymal stromal cells
JF  - MRS communications / a publication of the Materials Research Society
N2  - Toll-like receptor (TLR) can trigger an immune response against virus including SARS-CoV-2. TLR expression/distribution is varying in mesenchymal stromal cells (MSCs) depending on their culture environments. Here, to explore the effect of periodic thermomechanical cues on TLRs, thermally controlled shape-memory polymer sheets with programmable actuation capacity were created. The proportion of MSCs expressing SARS-CoV-2-associated TLRs was increased upon stimulation. The TLR4/7 colocalization was promoted and retained in the endoplasmic reticula. The TLR redistribution was driven by myosin-mediated F-actin assembly. These results highlight the potential of boosting the immunity for combating COVID-19 via thermomechanical preconditioning of MSCs.
KW  - Actuation
KW  - Antiviral
KW  - Biomaterial
KW  - COVID-19
KW  - Shape memory
Y1  - 2021
U6  - https://doi.org/10.1557/s43579-021-00049-5
SN  - 2159-6859
SN  - 2159-6867
VL  - 11
IS  - 4
SP  - 425
EP  - 431
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Schulze, Nicole
A1  - Koetz, Joachim
T1  - Kinetically controlled growth of gold nanotriangles in a vesicular template phase by adding a strongly alternating polyampholyte
JF  - Journal of dispersion science and technology
N2  - This paper is focused on the temperature-dependent synthesis of gold nanotriangles in a vesicular template phase, containing phosphatidylcholine and AOT, by adding the strongly alternating polyampholyte PalPhBisCarb.
UV-vis absorption spectra in combination with TEM micrographs show that flat gold nanoplatelets are formed predominantly in the presence of the polyampholyte at 45°C. The formation of triangular and hexagonal nanoplatelets can be directly influenced by the kinetic approach, i.e., by varying the polyampholyte dosage rate at 45°C. Corresponding zeta potential measurements indicate that a temperature-dependent adsorption of the polyampholyte on the {111} faces will induce the symmetry breaking effect, which is responsible for the kinetically controlled hindered vertical and preferred lateral growth of the nanoplatelets.
KW  - Kinetically controlled nanocrystal growth
KW  - nanotriangles
KW  - polyampholytes
Y1  - 2016
U6  - https://doi.org/10.1080/01932691.2016.1220318
SN  - 0193-2691
SN  - 1532-2351
VL  - 38
IS  - 8
SP  - 1073
EP  - 1078
PB  - Taylor & Francis
CY  - Philadelphia
ER  - 
TY  - JOUR
A1  - Deng, Zijun
A1  - Wang, Weiwei
A1  - Xu, Xun
A1  - Ma, Nan
A1  - Lendlein, Andreas
T1  - Polydopamine-based biofunctional substrate coating promotes mesenchymal stem cell migration
JF  - MRS advances : a journal of the Materials Research Society (MRS)
N2  - Rapid migration of mesenchymal stem cells (MSCs) on device surfaces could support in vivo tissue integration and might facilitate in vitro organoid formation. Here, polydopamine (PDA) is explored as a biofunctional coating to effectively promote MSC motility. It is hypothesized that PDA stimulates fibronectin deposition and in this way enhances integrin-mediated migration capability. The random and directional cell migration was investigated by time-lapse microscopy and gap closure assay respectively, and analysed with softwares as computational tools. A higher amount of deposited fibronectin was observed on PDA substrate, compared to the non-coated substrate. The integrin beta 1 activation and focal adhesion kinase (FAK) phosphorylation at Y397 were enhanced on PDA substrate, but the F-actin cytoskeleton was not altered, suggesting MSC migration on PDA was regulated by integrin initiated FAK signalling. This study strengthens the biofunctionality of PDA coating for regulating stem cells and offering a way of facilitating tissue integration of devices.
Y1  - 2021
U6  - https://doi.org/10.1557/s43580-021-00091-4
SN  - 2059-8521
VL  - 6
IS  - 31
SP  - 739
EP  - 744
PB  - Springer Nature Switzerland AG
CY  - Cham
ER  - 
TY  - JOUR
A1  - Machatschek, Rainhard Gabriel
A1  - Saretia, Shivam
A1  - Lendlein, Andreas
T1  - Assessing the influence of temperature-memory creation on the degradation of copolyesterurethanes in ultrathin films
JF  - Advanced materials interfaces
N2  - Copolyesterurethanes (PDLCLs) based on oligo(epsilon-caprolactone) (OCL) and oligo(omega-pentadecalactone) (OPDL) segments are biodegradable thermoplastic temperature-memory polymers. The temperature-memory capability in these polymers with crystallizable control units is implemented by a thermomechanical programming process causing alterations in the crystallite arrangement and chain organization. These morphological changes can potentially affect degradation. Initial observations on the macroscopic level inspire the hypothesis that switching of the controlling units causes an accelerated degradation of the material, resulting in programmable degradation by sequential coupling of functions. Hence, detailed degradation studies on Langmuir films of a PDLCL with 40 wt% OPDL content are carried out under enzymatic catalysis. The temperature-memory creation procedure is mimicked by compression at different temperatures. The evolution of the chain organization and mechanical properties during the degradation process is investigated by means of polarization-modulated infrared reflection absorption spectroscopy, interfacial rheology and to some extend by X-ray reflectivity. The experiments on PDLCL Langmuir films imply that degradability is not enhanced by thermal switching, as the former depends on the temperature during cold programming. Nevertheless, the thin film experiments show that the leaching of OCL segments does not induce further crystallization of the OPDL segments, which is beneficial for a controlled and predictable degradation.
KW  - block copolymers
KW  - degradation
KW  - Langmuir monolayers
KW  - rheology
KW  - temperature-memory polymers
Y1  - 2021
U6  - https://doi.org/10.1002/admi.202001926
SN  - 2196-7350
VL  - 8
IS  - 6
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Sperlich, Eric
A1  - Köckerling, Martin
T1  - The double cluster compound [Nb6Cl14(MeCN)(4)] [Nb6Cl14(pyz)(4)].6MeCN (Me: methyl, pyz: pyrazine) with a layered structure resulting from weak intermolecular interactions
JF  - Zeitschrift für Naturforschung
N2  - The synthesis and the crystal structure of the double cluster compound [Nb6Cl14(MeCN)(4)][Nb6Cl14(pyz)(4)]middot6CH(3)CN are described. The synthesis is based on a partial ligand exchange reaction, which proceeds upon dissolving [Nb6Cl14(pyz)(4)]middot2CH(2)Cl(2) in acetonitrile. The compound is built up of two discrete neutral cluster units, which consist of octahedra of Nb-6 atoms coordinated by 12 edge-bridging chlorido and two terminal chlorido ligands, and four acetonitrile ligands on one and four pyrazine ligands on the other cluster unit. Co-crystallized acetonitrile molecules are also present. The single-crystal structure determination has revealed a cluster arrangement in which the [Nb6Cl14(pyz)(4)] units are connected by (halogen) lone-pair-(pyrazine) pi interactions. These lead to chains of [Nb6Cl14(pyz)(4)] clusters. These chains are further connected to cluster layers by (nitrile-halogen) dipole-dipole interactions, in which the [Nb6Cl14(MeCN)(4)] and co-crystallized MeCN molecules are also involved. These cluster layers are arranged parallel to the crystallographic {011} plane.
KW  - cluster
KW  - crystal structure
KW  - dipole-dipole interaction
KW  - halide
KW  - lone-pair-pi interactions
KW  - niobium
Y1  - 2023
U6  - https://doi.org/10.1515/znb-2023-0001
SN  - 0932-0776
SN  - 1865-7117
VL  - 78
IS  - 5
SP  - 279
EP  - 283
PB  - De Gruyter
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Kreuzer, Lucas
A1  - Widmann, Tobias
A1  - Geiger, Christina
A1  - Wang, Peixi
A1  - Vagias, Apostolos N.
A1  - Heger, Julian Eliah
A1  - Haese, Martin
A1  - Hildebrand, Viet
A1  - Laschewsky, André
A1  - Papadakis, Christine M.
A1  - Müller-Buschbaum, Peter
T1  - Salt-dependent phase transition behavior of doubly thermoresponsive poly(sulfobetaine)-based diblock copolymer thin films
JF  - Langmuir : the ACS journal of surfaces and colloids / American Chemical Society
N2  - The water vapor-induced swelling, as well as subsequent phase-transition kinetics, of thin films of a diblock copolymer (DBC) loaded with different amounts of the salt NaBr, is investigated in situ. In dilute aqueous solution, the DBC features an orthogonally thermoresponsive behavior. It consists of a zwitterionic poly(sulfobetaine) block, namely, poly(4-(N-(3'-methacrylamidopropyl)-N, N-dimethylammonio) butane-1-sulfonate) (PSBP), showing an upper critical solution temperature, and a nonionic block, namely, poly(N-isopropylmethacrylamide) (PNIPMAM), exhibiting a lower critical solution temperature. The swelling kinetics in D2O vapor at 15 degrees C and the phase transition kinetics upon heating the swollen film to 60 degrees C and cooling back to 15 degrees C are followed with simultaneous time-of-flight neutron reflectometry and spectral reflectance measurements. These are complemented by Fourier transform infrared spectroscopy. The collapse temperature of PNIPMAM and the swelling temperature of PSBP are found at lower temperatures than in aqueous solution, which is attributed to the high polymer concentration in the thin-film geometry. Upon inclusion of sub-stoichiometric amounts (relative to the monomer units) of NaBr in the films, the water incorporation is significantly increased. This increase is mainly attributed to a salting-in effect on the zwitterionic PSBP block. Whereas the addition of NaBr notably shifts the swelling temperature of PSBP to lower temperatures, the collapse temperature of PNIPMAM remains unaffected by the presence of salt in the films.
Y1  - 2021
U6  - https://doi.org/10.1021/acs.langmuir.1c01342
SN  - 0743-7463
SN  - 1520-5827
VL  - 37
IS  - 30
SP  - 9179
EP  - 9191
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Pessanha, Tatiana
A1  - Paschoalino, Waldemir J.
A1  - Deroco, Patricia B.
A1  - Kogikoski Junior, Sergio
A1  - Moraes, Ana C. M. de
A1  - Carvalho Castro de Silva, Cecilia de
A1  - Kubota, Lauro T.
T1  - Interfacial capacitance of graphene oxide films electrodes
BT  - Fundamental studies on electrolytes interface aiming (bio)sensing applications
JF  - Electroanalysis : an internatinal journal devoted to electroanalysis, sensors and bioelectronic devices
N2  - The understanding of bidimensional materials dynamics and its electrolyte interface equilibrium, such as graphene oxide (GO), is critical for the development of a capacitive biosensing platform. The interfacial capacitance (C-i) of graphene-based materials may be tuned by experimental conditions such as pH optimization and cation size playing key roles at the enhancement of their capacitive properties allowing their application as novel capacitive biosensors. Here we reported a systematic study of C-i of multilayer GO films in different aqueous electrolytes employing electrochemical impedance spectroscopy for the application in a capacitive detection system. We demonstrated that the presence of ionizable oxygen-containing functional groups within multilayer GO film favors the interactions and the accumulation of cations in the structure of the electrodes enhancing the GO C-i in aqueous solutions, where at pH 7.0 (the best condition) the C-i was 340 mu F mg(-1) at -0.01 V vs Ag/AgCl. We also established that the hydrated cation radius affects the mobility and interaction with GO functional groups and it plays a critical role in the Ci, as demonstrated in the presence of different cations Na+=640 mu F mg(-1), Li+=575 mu F mg(-1) and TMA(+)=477 mu F mg(-1). As a proof-of-concept, the capacitive behaviour of GO was explored as biosensing platform for standard streptavidin-biotin systems. For this system, the C-i varied linearly with the log of the concentration of the targeting analyte in the range from 10 pg mL(-1) to 100 ng mL(-1), showing the promising applicability of capacitive GO based sensors for label-free biosensing.
KW  - Interfacial capacitance
KW  - Graphene oxide
KW  - Functional groups
KW  - Electrochemical impedance
KW  - Graphene derivates
Y1  - 2021
U6  - https://doi.org/10.1002/elan.202100220
SN  - 1521-4109
VL  - 34
IS  - 4
SP  - 692
EP  - 700
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Wang, Peixi
A1  - Geiger, Christina
A1  - Kreuzer, Lucas
A1  - Widmann, Tobias
A1  - Reitenbach, Julija
A1  - Liang, Suzhe
A1  - Cubitt, Robert
A1  - Henschel, Cristiane
A1  - Laschewsky, André
A1  - Papadakis, Christine M.
A1  - Müller-Buschbaum, Peter
T1  - Poly(sulfobetaine)-based diblock copolymer thin films in water/acetone atmosphere: modulation of water hydration and co-nonsolvency-triggered film contraction
JF  - Langmuir : the ACS journal of surfaces and colloids
N2  - The water swelling and subsequent solvent exchange including co-nonsolvency behavior of thin films of a doubly thermo-responsive diblock copolymer (DBC) are studied viaspectral reflectance, time-of-flight neutron reflectometry, and Fourier transform infrared spectroscopy. 
The DBC consists of a thermo-responsive zwitterionic (poly(4-((3-methacrylamidopropyl) dimethylammonio) butane-1-sulfonate)) (PSBP) block, featuring an upper critical solution temperature transition in aqueous media but being insoluble in acetone, and a nonionic poly(N-isopropylmethacrylamide) (PNIPMAM) block, featuring a lower critical solution temperature transition in water, while being soluble in acetone. 
Homogeneous DBC films of 50-100 nm thickness are first swollen in saturated water vapor (H2OorD2O), before they are subjected to a contraction process by exposure to mixed saturated water/acetone vapor (H2OorD2O/acetone-d6 = 9:1 v/v).
The affinity of the DBC film toward H2O is stronger than for D2O, as inferred from the higher film thickness in the swollen state and the higher absorbed water content, thus revealing a pronounced isotope sensitivity. 
During the co-solvent-induced switching by mixed water/acetone vapor, a two-step film contraction is observed, which is attributed to the delayed expulsion of water molecules and uptake of acetone molecules. 
The swelling kinetics are compared for both mixed vapors (H2O/acetone-d6 and D2O/acetone-d6) and with those of the related homopolymer films. 
Moreover, the concomitant variations of the local environment around the hydrophilic groups located in the PSBP and PNIPMAM blocks are followed. 
The first contraction step turns out to be dominated by the behavior of the PSBP block, where as the second one is dominated by the PNIPMAM block. 
The unusual swelling and contraction behavior of the latter block is attributed to its co-nonsolvency behavior. 
Furthermore, we observe cooperative hydration effects in the DBC films, that is, both polymer blocks influence each other's solvation behavior.
Y1  - 2022
U6  - https://doi.org/10.1021/acs.langmuir.2c00451
SN  - 0743-7463
SN  - 1520-5827
VL  - 38
IS  - 22
SP  - 6934
EP  - 6948
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Kuntze, Kim
A1  - Viljakka, Jani
A1  - Titov, Evgenii
A1  - Ahmed, Zafar
A1  - Kalenius, Elina
A1  - Saalfrank, Peter
A1  - Priimagi, Arri
T1  - Towards low-energy-light-driven bistable photoswitches
BT  - ortho-fluoroaminoazobenzenes
JF  - Photochemical & photobiological sciences / European Society for Photobiology
N2  - Thermally stable photoswitches that are driven with low-energy light are rare, yet crucial for extending the applicability of photoresponsive molecules and materials towards, e.g., living systems. Combined ortho-fluorination and -amination couples high visible light absorptivity of o-aminoazobenzenes with the extraordinary bistability of o-fluoroazobenzenes. Herein, we report a library of easily accessible o-aminofluoroazobenzenes and establish structure-property relationships regarding spectral qualities, visible light isomerization efficiency and thermal stability of the cis-isomer with respect to the degree of o-substitution and choice of amino substituent. We rationalize the experimental results with quantum chemical calculations, revealing the nature of low-lying excited states and providing insight into thermal isomerization. The synthesized azobenzenes absorb at up to 600 nm and their thermal cis-lifetimes range from milliseconds to months. The most unique example can be driven from trans to cis with any wavelength from UV up to 595 nm, while still exhibiting a thermal cis-lifetime of 81 days. <br /> [GRAPHICS] <br /> .
Y1  - 2022
U6  - https://doi.org/10.1007/s43630-021-00145-4
SN  - 1474-905X
SN  - 1474-9092
VL  - 21
IS  - 2
SP  - 159
EP  - 173
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - JOUR
A1  - Xie, Dongjiu
A1  - Xu, Yaolin
A1  - Wang, Yonglei
A1  - Pan, Xuefeng
A1  - Härk, Eneli
A1  - Kochovski, Zdravko
A1  - Eljarrat, Alberto
A1  - Müller, Johannes
A1  - Koch, Christoph T.
A1  - Yuan, Jiayin
A1  - Lu, Yan
T1  - Poly(ionic liquid) nanovesicle-templated carbon nanocapsules functionalized with uniform iron nitride nanoparticles as catalytic sulfur host for Li-S batteries
JF  - ACS nano
N2  - Poly(ionic liquid)s (PIL) are common precursors for heteroatom-doped carbon materials. Despite a relatively higher carbonization yield, the PIL-to-carbon conversion process faces challenges in preserving morphological and structural motifs on the nanoscale. Assisted by a thin polydopamine coating route and ion exchange, imidazoliumbased PIL nanovesicles were successfully applied in morphology-maintaining carbonization to prepare carbon composite nanocapsules. Extending this strategy further to their composites, we demonstrate the synthesis of carbon composite nanocapsules functionalized with iron nitride nanoparticles of an ultrafine, uniform size of 3-5 nm (termed "FexN@C "). Due to its unique nanostructure, the sulfur-loaded FexN@C electrode was tested to efficiently mitigate the notorious shuttle effect of lithium polysulfides (LiPSs) in Li-S batteries. The cavity of the carbon nanocapsules was spotted to better the loading content of sulfur. The well-dispersed iron nitride nanoparticles effectively catalyze the conversion of LiPSs to Li2S, owing to their high electronic conductivity and strong binding power to LiPSs. Benefiting from this well-crafted composite nanostructure, the constructed FexN@C/S cathode demonstrated a fairly high discharge capacity of 1085 mAh g(-1) at 0.5 C initially, and a remaining value of 930 mAh g(-1 )after 200 cycles. In addition, it exhibits an excellent rate capability with a high initial discharge capacity of 889.8 mAh g(-1) at 2 C. This facile PIL-to-nanocarbon synthetic approach is applicable for the exquisite design of complex hybrid carbon nanostructures with potential use in electrochemical energy storage and conversion.
KW  - poly(ionic liquid)s
KW  - nanovesicles
KW  - sulfur host
KW  - iron nitride
KW  - Li-S
KW  - batteries
Y1  - 2022
U6  - https://doi.org/10.1021/acsnano.2c01992
SN  - 1936-0851
SN  - 1936-086X
VL  - 16
IS  - 7
SP  - 10554
EP  - 10565
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Neffe, Axel T.
A1  - Löwenberg, Candy
A1  - Julich-Gruner, Konstanze K.
A1  - Behl, Marc
A1  - Lendlein, Andreas
T1  - Thermally-induced shape-memory behavior of degradable gelatin-based networks
JF  - International journal of molecular sciences
N2  - Shape-memory hydrogels (SMH) are multifunctional, actively-moving polymers of interest in biomedicine. In loosely crosslinked polymer networks, gelatin chains may form triple helices, which can act as temporary net points in SMH, depending on the presence of salts. Here, we show programming and initiation of the shape-memory effect of such networks based on a thermomechanical process compatible with the physiological environment. The SMH were synthesized by reaction of glycidylmethacrylated gelatin with oligo(ethylene glycol) (OEG) alpha,omega-dithiols of varying crosslinker length and amount. Triple helicalization of gelatin chains is shown directly by wide-angle X-ray scattering and indirectly via the mechanical behavior at different temperatures. The ability to form triple helices increased with the molar mass of the crosslinker. Hydrogels had storage moduli of 0.27-23 kPa and Young's moduli of 215-360 kPa at 4 degrees C. The hydrogels were hydrolytically degradable, with full degradation to water-soluble products within one week at 37 degrees C and pH = 7.4. A thermally-induced shape-memory effect is demonstrated in bending as well as in compression tests, in which shape recovery with excellent shape-recovery rates R-r close to 100% were observed. In the future, the material presented here could be applied, e.g., as self-anchoring devices mechanically resembling the extracellular matrix.
KW  - shape-memory hydrogel
KW  - active polymer
KW  - biopolymer
KW  - mechanical
KW  - properties
KW  - degradation
Y1  - 2021
U6  - https://doi.org/10.3390/ijms22115892
SN  - 1422-0067
SN  - 1661-6596
VL  - 22
IS  - 11
PB  - Molecular Diversity Preservation International
CY  - Basel
ER  - 
TY  - JOUR
A1  - Bochove, Bas van
A1  - Grijpma, Dirk W.
A1  - Lendlein, Andreas
A1  - Seppälä, Jukka
T1  - Designing advanced functional polymers for medicine
JF  - European polymer journal : EPJ
Y1  - 2021
U6  - https://doi.org/10.1016/j.eurpolymj.2021.110573
SN  - 0014-3057
VL  - 155
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Hwang, Jinyeon
A1  - Zhang, Wuyong
A1  - Youk, Sol
A1  - Schutjajew, Konstantin
A1  - Oschatz, Martin
T1  - Understanding structure-property relationships under experimental conditions for the optimization of lithium-ion capacitor anodes based on all-carbon-composite materials
JF  - Energy technology : generation, conversion, storage, distribution
N2  - The nanoscale combination of a conductive carbon and a carbon-based material with abundant heteroatoms for battery electrodes is a method to overcome the limitation that the latter has high affinity to alkali metal ions but low electronic conductivity. The synthetic protocol and the individual ratios and structures are important aspects influencing the properties of such multifunctional compounds. Their interplay is, herein, investigated by infiltration of a porous ZnO-templated carbon (ZTC) with nitrogen-rich carbon obtained by condensation of hexaazatriphenylene-hexacarbonitrile (HAT-CN) at 550-1000 degrees C. The density of lithiophilic sites can be controlled by HAT-CN content and condensation temperature. Lithium storage properties are significantly improved in comparison with those of the individual compounds and their physical mixtures. Depending on the uniformity of the formed composite, loading ratio and condensation temperature have different influence. Most stable operation at high capacity per used monomer is achieved with a slowly dried composite with an HAT-CN:ZTC mass ratio of 4:1, condensed at 550 degrees C, providing more than 400 mAh g(-1) discharge capacity at 0.1 A g(-1) and a capacity retention of 72% after 100 cycles of operation at 0.5 A g(-1) due to the homogeneity of the composite and high content of lithiophilic sites.
KW  - anodes
KW  - hybrid materials
KW  - nitrogen-doped carbon
KW  - porous carbon
KW  - lithium-ion capacitors
Y1  - 2021
U6  - https://doi.org/10.1002/ente.202001054
SN  - 2194-4296
VL  - 9
IS  - 3
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Pan, Xuefeng
A1  - Sarhan, Radwan Mohamed
A1  - Kochovski, Zdravko
A1  - Chen, Guosong
A1  - Taubert, Andreas
A1  - Mei, Shilin
A1  - Lu, Yan
T1  - Template synthesis of dual-functional porous MoS2 nanoparticles with photothermal conversion and catalytic properties
JF  - Nanoscale
N2  - Advanced catalysis triggered by photothermal conversion effects has aroused increasing interest due to its huge potential in environmental purification. 
In this work, we developed a novel approach to the fast degradation of 4-nitrophenol (4-Nip) using porous MoS2 nanoparticles as catalysts, which integrate the intrinsic catalytic property of MoS2 with its photothermal conversion capability. 
Using assembled polystyrene-b-poly(2-vinylpyridine) block copolymers as soft templates, various MoS 2 particles were prepared, which exhibited tailored morphologies (e.g., pomegranate-like, hollow, and open porous structures). 
The photothermal conversion performance of these featured particles was compared under near-infrared (NIR) light irradiation. 
Intriguingly, when these porous MoS2 particles were further employed as catalysts for the reduction of 4-Nip, the reaction rate constant was increased by a factor of 1.5 under NIR illumination. 
We attribute this catalytic enhancement to the open porous architecture and light-to-heat conversion performance of the MoS2 particles. This contribution offers new opportunities for efficient photothermal-assisted catalysis.
Y1  - 2022
U6  - https://doi.org/10.1039/d2nr01040b
SN  - 2040-3372
VL  - 14
IS  - 18
SP  - 6888
EP  - 6901
PB  - RSC Publ. (Royal Society of Chemistry)
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Zhao, Yuhang
A1  - Sarhan, Radwan Mohamed
A1  - Eljarrat, Alberto
A1  - Kochovski, Zdravko
A1  - Koch, Christoph
A1  - Schmidt, Bernd
A1  - Koopman, Wouter-Willem Adriaan
A1  - Lu, Yan
T1  - Surface-functionalized Au-Pd nanorods with enhanced photothermal conversion and catalytic performance
JF  - ACS applied materials & interfaces
N2  - Bimetallic nanostructures comprising plasmonic and catalytic components have recently emerged as a promising approach to generate a new type of photo-enhanced nanoreactors. Most designs however concentrate on plasmon-induced charge separation, leaving photo-generated heat as a side product. 
This work presents a photoreactor based on Au-Pd nanorods with an optimized photothermal conversion, which aims to effectively utilize the photo-generated heat to increase the rate of Pd-catalyzed reactions. Dumbbell-shaped Au nanorods were fabricated via a seed-mediated growth method using binary surfactants. Pd clusters were selectively grown at the tips of the Au nanorods, using the zeta potential as a new synthetic parameter to indicate the surfactant remaining on the nanorod surface. 
The photothermal conversion of the Au-Pd nanorods was improved with a thin layer of polydopamine (PDA) or TiO2. 
As a result, a 60% higher temperature increment of the dispersion compared to that for bare Au rods at the same light intensity and particle density could be achieved. 
The catalytic performance of the coated particles was then tested using the reduction of 4-nitrophenol as the model reaction. Under light, the PDA-coated Au-Pd nanorods exhibited an improved catalytic activity, increasing the reaction rate by a factor 3. 
An analysis of the activation energy confirmed the photoheating effect to be the dominant mechanism accelerating the reaction. Thus, the increased photothermal heating is responsible for the reaction acceleration. 
Interestingly, the same analysis shows a roughly 10% higher reaction rate for particles under illumination compared to under dark heating, possibly implying a crucial role of localized heat gradients at the particle surface. 
Finally, the coating thickness was identified as an essential parameter determining the photothermal conversion efficiency and the reaction acceleration.
KW  - Au-Pd nanorods
KW  - PDA
KW  - photothermal conversion
KW  - surface plasmon
KW  - 4-nitrophenol
Y1  - 2022
U6  - https://doi.org/10.1021/acsami.2c00221
SN  - 1944-8244
SN  - 1944-8252
VL  - 14
IS  - 15
SP  - 17259
EP  - 17272
PB  - American Chemical Society
CY  - Washington, DC
ER  - 
TY  - JOUR
A1  - Floyd, Thomas G.
A1  - Song, Ji-Inn
A1  - Hapeshi, Alexia
A1  - Laroque, Sophie
A1  - Hartlieb, Matthias
A1  - Perrier, Sebastien
T1  - Bottlebrush copolymers for gene delivery: influence of architecture, charge density, and backbone length on transfection efficiency
JF  - Journal of materials chemistry : B, materials for biology and medicine
N2  - The influence of polymer architecture of polycations on their ability to transfect mammalian cells is probed. Polymer bottle brushes with grafts made from partially hydrolysed poly(2-ethyl-2-oxazoline) are used while varying the length of the polymer backbone as well as the degree of hydrolysis (cationic charge content). Polyplex formation is investigated via gel electrophoresis, dye-displacement and dynamic light scattering. Bottle brushes show a superior ability to complex pDNA when compared to linear copolymers. Also, nucleic acid release was found to be improved by a graft architecture. Polyplexes based on bottle brush copolymers showed an elongated shape in transmission electron microscopy images. The cytotoxicity against mammalian cells is drastically reduced when a graft architecture is used instead of linear copolymers. Moreover, the best-performing bottle brush copolymer showed a transfection ability comparable with that of linear poly(ethylenimine), the gold standard of polymeric transfection agents, which is used as positive control. In combination with their markedly lowered cytotoxicity, cationic bottle brush copolymers are therefore shown to be a highly promising class of gene delivery vectors.
Y1  - 2022
U6  - https://doi.org/10.1039/d2tb00490a
SN  - 2050-750X
SN  - 2050-7518
VL  - 10
IS  - 19
SP  - 3696
EP  - 3704
PB  - Royal Society of Chemistry
CY  - London [u.a.]
ER  - 
TY  - JOUR
A1  - Abbasi, Ali
A1  - Xu, Yaolin
A1  - Khezri, Ramin
A1  - Etesami, Mohammad
A1  - Lin, C.
A1  - Kheawhom, Soorathep
A1  - Lu, Yan
T1  - Advances in characteristics improvement of polymeric membranes/separators for zinc-air batteries
JF  - Materials Today Sustainability
N2  - Zinc-air batteries (ZABs) are gaining popularity for a wide range of applications due to their high energy density, excellent safety, and environmental friendliness. A membrane/separator is a critical component of ZABs, with substantial implications for battery performance and stability, particularly in the case of a battery in solid state format, which has captured increased attention in recent years. In this review, recent advances as well as insight into the architecture of polymeric membrane/separators for ZABs including porous polymer separators (PPSs), gel polymer electrolytes (GPEs), solid polymer electrolytes (SPEs) and anion exchange membranes (AEMs) are discussed. The paper puts forward strategies to enhance stability, ionic conductivity, ionic selectivity, electrolyte storage capacity and mechanical properties for each type of polymeric membrane. In addition, the remaining major obstacles as well as the most potential avenues for future research are examined in detail.
KW  - Ionic selectivity
KW  - Ionic conductivity
KW  - Gel polymer
KW  - Ion exchange
KW  - Porous
KW  - polymer
Y1  - 2022
U6  - https://doi.org/10.1016/j.mtsust.2022.100126
SN  - 2589-2347
VL  - 18
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Mayer, Dennis
A1  - Picconi, David
A1  - Robinson, Matthew S.
A1  - Gühr, Markus
T1  - Experimental and theoretical gas-phase absorption spectra of thionated uracils
JF  - Chemical physics : a journal devoted to experimental and theoretical research involving problems of both a chemical and physical nature
N2  - We present a comparative study of the gas-phase UV spectra of uracil and its thionated counterparts (2-thiouracil, 4-thiouracil and 2,4-dithiouracil), closely supported by time-dependent density functional theory calculations to assign the transitions observed. We systematically discuss pure gas-phase spectra for the (thio)uracils in the range of 200-400 nm (similar to 3.2-6.4 eV), and examine the spectra of all four species with a single theoretical approach. We note that specific vibrational modelling is needed to accurately determine the spectra across the examined wavelength range, and systematically model the transitions that appear at wavelengths shorter than 250 nm. Additionally, we find in the cases of 2-thiouracil and 2,4-dithiouracil, that the gas-phase spectra deviate significantly from some previously published solution-phase spectra, especially those collected in basic environments.
KW  - Thiouracil
KW  - Uracil
KW  - UV-VIS Spectroscopy
KW  - Excited-state calculations;
KW  - TD-DFT
KW  - Gas phase
Y1  - 2022
U6  - https://doi.org/10.1016/j.chemphys.2022.111500
SN  - 0301-0104
VL  - 558
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Zimmermann, Marc
A1  - Stomps, Benjamin René Harald
A1  - Schulte-Osseili, Christine
A1  - Grigoriev, Dmitry
A1  - Ewen, Dirk
A1  - Morgan, Andrew
A1  - Böker, Alexander
T1  - Organic dye anchor peptide conjugates as an advanced coloring agent for polypropylene yarn
JF  - Textile Research Journal
N2  - Polypropylene as one of the world's top commodity polymers is also widely used in the textile industry. However, its non-polar nature and partially crystalline structure significantly complicate the process of industrial coloring of polypropylene. Currently, textiles made of polypropylene or with a significant proportion of polypropylene are dyed under quite harsh conditions, including the use of high pressures and temperatures, which makes this process energy intensive. This research presents a three-step synthesis of coloring agents, capable of adhering onto synthetic polypropylene yarns without harsh energy-consuming conditions. This is possible by encapsulation of organic pigments using trimethoxyphenylsilane, introduction of surface double bonds via modification of the silica shell with trimethoxysilylpropylmethacrylate and final attachment of highly adhesive anchor peptides using thiol-ene chemistry. We demonstrate the applicability of this approach by dyeing polypropylene yarns in a simple process under ambient conditions after giving a step-by-step guide for the synthesis of these new dyeing agents. Finally, the successful dyeing of the yarns is visualized, and its practicability is discussed.
KW  - anchor peptides
KW  - organic dye pigments
KW  - coloring agents
KW  - polypropylene
KW  - yarns
Y1  - 2020
U6  - https://doi.org/10.1177/0040517520932231
SN  - 0040-5175
SN  - 1746-7748
VL  - 91
IS  - 1-2
SP  - 28
EP  - 39
PB  - Sage Publ.
CY  - London
ER  - 
TY  - JOUR
A1  - Ilic, Ivan
A1  - Schutjajew, Konstantin
A1  - Zhang, Wuyong
A1  - Oschatz, Martin
T1  - Changes of porosity of hard carbons during mechanical treatment and the relevance for sodium-ion anodes
JF  - Carbon : an international journal sponsored by the American Carbon Society
N2  - Lithium-ion batteries have revolutionized battery technology. However, the scarcity of lithium in nature is driving the search for alternatives. For that reason, sodium-ion batteries have attracted increasing attention in recent years. The main obstacle to their development is the anode as, unlike for lithium-ion batteries, graphite cannot be used due to the inability to form stoichiometrically useful intercalation compounds with sodium. A promising candidate for sodium storage is hard carbon a form of nongraphitisable carbon, that can be synthesized from various precursor materials. Processing of hard carbons is often done by using mechanochemical treatments. Although it is generally accepted and often observed that they can influence the porosity of hard carbons, their effect on battery performance not well understood. Here, the changes in porosity occurring during ball milling are elucidated and related to the properties of hard carbons in sodium storage. Analysis by combined gas physisorption and small angle X-ray scattering shows that porosity changes during ball milling with a significant increase of the open porosity, unsuitable for reversible sodium storage, and decrease of the closed porosity, suitable for reversible sodium storage. While pristine hard carbon can store 58.5 mAh g(-1) in the closed pores, upon 5 h of mechanical treatment in a ball mill it can only store 35.5 mAh g(-1). The obtained results are furthermore pointing towards the disputed "intercalation-adsorption" mechanism.
KW  - Hard carbons
KW  - Sodium-ion batteries
KW  - Anodes
KW  - Microporosity
KW  - Ball milling
Y1  - 2022
U6  - https://doi.org/10.1016/j.carbon.2021.09.063
SN  - 0008-6223
SN  - 1873-3891
VL  - 186
SP  - 55
EP  - 63
PB  - Elsevier Science
CY  - Amsterdam [u.a.]
ER  - 
TY  - JOUR
A1  - Gupta, Banshi D.
A1  - Pathak, Anisha
A1  - Shrivastav, Anand
T1  - Optical Biomedical Diagnostics Using Lab-on-Fiber Technology
BT  - a review
JF  - Photonics : open access journal
N2  - Point-of-care and in-vivo bio-diagnostic tools are the current need for the present critical scenarios in the healthcare industry. The past few decades have seen a surge in research activities related to solving the challenges associated with precise on-site bio-sensing. Cutting-edge fiber optic technology enables the interaction of light with functionalized fiber surfaces at remote locations to develop a novel, miniaturized and cost-effective lab on fiber technology for bio-sensing applications. The recent remarkable developments in the field of nanotechnology provide innumerable functionalization methodologies to develop selective bio-recognition elements for label free biosensors. These exceptional methods may be easily integrated with fiber surfaces to provide highly selective light-matter interaction depending on various transduction mechanisms. In the present review, an overview of optical fiber-based biosensors has been provided with focus on physical principles used, along with the functionalization protocols for the detection of various biological analytes to diagnose the disease. The design and performance of these biosensors in terms of operating range, selectivity, response time and limit of detection have been discussed. In the concluding remarks, the challenges associated with these biosensors and the improvement required to develop handheld devices to enable direct target detection have been highlighted.
KW  - fiber optic sensors
KW  - synthesis
KW  - interferometry
KW  - fluorescence
KW  - SERS
KW  - SPR
KW  - immunosensors
KW  - enzymatic sensors
KW  - molecular imprinted polymers
Y1  - 2022
U6  - https://doi.org/10.3390/photonics9020086
SN  - 2304-6732
VL  - 9
IS  - 2
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Akampurira, Denis
A1  - Akala, Hoseah M.
A1  - Derese, Solomon
A1  - Heydenreich, Matthias
A1  - Yenesew, Abiy
T1  - A new C-C linked benzophenathridine-2-quinoline dimer, and the antiplasmodial activity of alkaloids from Zanthoxylum holstzianum
JF  - Natural product research
N2  - The CH2Cl2/MeOH (1:1) extract of Zanthoxylum holstzianum stem bark showed good antiplasmodial activity (IC50 2.5 +/- 0.3 and 2.6 +/- 0.3 mu g/mL against the W2 and D6 strains of Plasmodium falciparum, respectively). From the extract five benzophenanthridine alkaloids [8-acetonyldihydrochelerythrine (1), nitidine (2), dihydrochelerythine (3), norchelerythrine (5), arnottianamide (8)]; a 2-quinolone alkaloid [N-methylflindersine (4)]; a lignan [4,4 '-dihydroxy-3,3 '-dimethoxylignan-9,9 '-diyl diacetate (7)] and a dimer of a benzophenanthridine and 2-quinoline [holstzianoquinoline (6)] were isolated. The CH2Cl2/MeOH (1:1) extract of the root bark afforded 1, 3-6, 8, chelerythridimerine (9) and 9-demethyloxychelerythrine (10). Holstzianoquinoline (6) is new, and is the second dimer linked by a C-C bond of a benzophenanthridine and a 2-quinoline reported thus far. The compounds were identified based on spectroscopic evidence. Amongst five compounds (1-5) tested against two strains of P. falciparum, nitidine (IC50 0.11 +/- 0.01 mu g/mL against W2 and D6 strains) and norchelerythrine (IC50 value of 0.15 +/- 0.01 mu g/mL against D6 strain) were the most active.
KW  - Antiplasmodial
KW  - benzophenanthridine alkaloid
KW  - holstzianoquinoline;
KW  - rutaceae
KW  - Zanthoxylum holstzianum
Y1  - 2022
U6  - https://doi.org/10.1080/14786419.2022.2034810
SN  - 1478-6419
SN  - 1478-6427
VL  - 37
IS  - 13
SP  - 2161
EP  - 2171
PB  - Taylor & Francis
CY  - London [u.a.]
ER  - 
TY  - JOUR
A1  - Kreuzer, Lucas
A1  - Lindenmeir, Christoph
A1  - Geiger, Christina
A1  - Widmann, Tobias
A1  - Hildebrand, Viet
A1  - Laschewsky, André
A1  - Papadakis, Christine M.
A1  - Müller-Buschbaum, Peter
T1  - Poly(sulfobetaine) versus poly(N-isopropylmethacrylamide)
BT  - co-nonsolvency-type behavior of thin films in a water/methanol atmosphere
JF  - Macromolecules : a publication of the American Chemical Society
N2  - The swelling and co-nonsolvency behaviors in pure H2O and in a mixed H2O/CH3OH vapor atmosphere of two different polar, water-soluble polymers in thin film geometry are studied in situ. Films of a zwitterionic poly(sulfobetaine), namely, poly[3-((2-(methacryloyloxy)ethyl)dimethylammonio) propane-1-sulfonate] (PSPE), and a polar nonionic polymer, namely, poly(N-isopropylmethacrylamide) (PNIPMAM), are investigated in real time by spectral reflectance (SR) measurements and Fourier transform infrared (FTIR) spectroscopy. Whereas PSPE is insoluble in methanol, PNIPMAM is soluble but exhibits cononsolvency behavior in water/methanol mixtures. First, the swelling of PSPE and PNIPMAM thin films in H2O vapor is followed. Subsequently, CH3OH is added to the vapor atmosphere, and its contracting effect on the water-swollen films is monitored, revealing a co-nonsolvency-type behavior for PNIPMAM and PSPE. SR measurements indicate that PSPE and PNIPMAM behave significantly different during the H2O swelling and subsequent exposure to CH3OH, not only with respect to the amounts of absorbed water and CH3OH, but also to the cosolvent-induced contraction mechanisms. While PSPE thin films exhibit an abrupt one-step contraction, the contraction of PNIPMAM thin films occurs in two steps. FTIR studies corroborate these findings on a molecular scale and reveal the role of the specific functional groups, both during the swelling and the cosolvent-induced switching of the solvation state.
Y1  - 2021
U6  - https://doi.org/10.1021/acs.macromol.0c02281
SN  - 0024-9297
SN  - 1520-5835
VL  - 54
IS  - 3
SP  - 1548
EP  - 1556
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Deng, Zijun
A1  - Wang, Weiwei
A1  - Xua, Xun
A1  - Gould, Oliver E. C.
A1  - Kratz, Karl
A1  - Ma, Nan
A1  - Lendlein, Andreas
T1  - Polymeric sheet actuators with programmable bioinstructivity
JF  - PNAS
N2  - Stem cells are capable of sensing and processing environmental inputs, converting this information to output a specific cell lineage through signaling cascades. Despite the combinatorial nature of mechanical, thermal, and biochemical signals, these stimuli have typically been decoupled and applied independently, requiring continuous regulation by controlling units. We employ a programmable polymer actuator sheet to autonomously synchronize thermal and mechanical signals applied to mesenchymal stem cells (MSC5). Using a grid on its underside, the shape change of polymer sheet, as well as cell morphology, calcium (Ca2+) influx, and focal adhesion assembly, could be visualized and quantified. This paper gives compelling evidence that the temperature sensing and mechanosensing of MSC5 are interconnected via intracellular Ca2+. Up-regulated Ca2+ levels lead to a remarkable alteration of histone H3K9 acetylation and activation of osteogenic related genes. The interplay of physical, thermal, and biochemical signaling was utilized to accelerate the cell differentiation toward osteogenic lineage. The approach of programmable bioinstructivity provides a fundamental principle for functional biomaterials exhibiting multifaceted stimuli on differentiation programs. Technological impact is expected in the tissue engineering of periosteum for treating bone defects.
KW  - reversible shape-memory actuator
KW  - mesenchymal stem cells
KW  - calcium influx
KW  - HDAC1
KW  - RUNX2
Y1  - 2020
U6  - https://doi.org/10.1073/pnas.1910668117
SN  - 1091-6490
VL  - 117
IS  - 4
SP  - 1895
EP  - 1901
PB  - National Academy of Sciences
CY  - Washington, DC
ER  - 
TY  - JOUR
A1  - Saretia, Shivam
A1  - Machatschek, Rainhard Gabriel
A1  - Lendlein, Andreas
T1  - Degradation kinetics of oligo(ε-caprolactone) ultrathin films
BT  - Influence of crystallinity
JF  - MRS advances : a journal of the Materials Research Society (MRS)
N2  - The potential of using crystallinity as morphological parameter to control polyester degradation in acidic environments is explored in ultrathin films by Langmuir technique. Films of hydroxy or methacrylate end-capped oligo(epsilon-caprolactone) (OCL) are prepared at the air-water interface as a function of mean molecular area (MMA). The obtained amorphous, partially crystalline or highly crystalline ultrathin films of OCL are hydrolytically degraded at pH similar to 1.2 on water surface or on silicon surface as-transferred films. A high crystallinity reduces the hydrolytic degradation rate of the films on both water and solid surfaces. Different acceleration rates of hydrolytic degradation of semi-crystalline films are achieved either by crystals complete melting, partially melting, or by heating them below their melting temperatures. Semi-crystalline OCL films transferred via water onto a solid surface retain their crystalline morphology, degrade in a controlled manner, and are of interest as thermoswitchable coatings for cell substrates and medical devices.
Y1  - 2021
U6  - https://doi.org/10.1557/s43580-021-00067-4
SN  - 2059-8521
VL  - 6
IS  - 33
SP  - 790
EP  - 795
PB  - Springer Nature Switzerland AG
CY  - Cham
ER  - 
TY  - JOUR
A1  - Yue, Yanhua
A1  - Melani, Giacomo
A1  - Kirsch, Harald
A1  - Paarmann, Alexander
A1  - Saalfrank, Peter
A1  - Campen, Richard Kramer
A1  - Tong, Yujin
T1  - Structure and Reactivity of a-Al2O3(0001) Surfaces: How Do Al-I and Gibbsite-like Terminations Interconvert?
JF  - The journal of physical chemistry / publ. weekly by the American Chemical Society. C, Energy, materials, and catalysis
N2  - The alpha-Al2O3(0001) surface has been extensively studied because of its significance in both fundamental research and application. Prior work suggests that in ultra-high-vacuum (UHV), in the absence of water, the so-called Al-I termination is thermodynamically favored, while in ambient, in contact with liquid water, a Gibbsite-like layer is created. While the view of the alpha- Al2O3(0001)/H2O(l) interface appears relatively clear in theory, experimental characterization of this system has resulted in estimates of surface acidity, i.e., isoelectric points, that differ by 4 pH units and surface structure that in some reports has non-hydrogen-bonded surface aluminol (Al-OH) groups and in others does not. In this study, we employed vibrational sum frequency spectroscopy (VSFS) and density functional theory (DFT) simulation to study the surface phonon modes of the differently terminated alpha-Al2O3(0001) surfaces in both UHV and ambient. We find that, on either water dosing of the Al-I in UHV or heat-induced dehydroxylation of the Gibbsite-like in ambient, the surfaces do not interconvert. This observation offers a new explanation for disagreements in prior work on the alpha-Al2O3(0001)/liquid water interface -different preparation methods may create surfaces that do not interconvert-and shows that the surface phonon spectral response offers a novel probe of interfacial hydrogen bonding structure.
Y1  - 2022
U6  - https://doi.org/10.1021/acs.jpcc.2c03743
SN  - 1932-7447
SN  - 1932-7455
VL  - 126
IS  - 31
SP  - 13467
EP  - 13476
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Tarazona Lizcano, Natalia Andrea
A1  - Machatschek, Rainhard Gabriel
A1  - Balcucho, Jennifer
A1  - Castro-Mayorga, Jinneth Lorena
A1  - Saldarriaga, Juan Francisco
A1  - Lendlein, Andreas
T1  - Opportunities and challenges for integrating the development of sustainable polymer materials within an international circular (bio)economy concept
JF  - MRS energy & sustainability : science & technology & socio-economics & policy
N2  - The production and consumption of commodity polymers have been an indispensable part of the development of our modern society. Owing to their adjustable properties and variety of functions, polymer-based materials will continue playing important roles in achieving the Sustainable Development Goals (SDG)s, defined by the United Nations, in key areas such as healthcare, transport, food preservation, construction, electronics, and water management. Considering the serious environmental crisis, generated by increasing consumption of plastics, leading-edge polymers need to incorporate two types of functions: Those that directly arise from the demands of the application (e.g. selective gas and liquid permeation, actuation or charge transport) and those that enable minimization of environmental harm, e.g., through prolongation of the functional lifetime, minimization of material usage, or through predictable disintegration into non-toxic fragments. Here, we give examples of how the incorporation of a thoughtful combination of properties/functions can enhance the sustainability of plastics ranging from material design to waste management. We focus on tools to measure and reduce the negative impacts of plastics on the environment throughout their life cycle, the use of renewable sources for their synthesis, the design of biodegradable and/or recyclable materials, and the use of biotechnological strategies for enzymatic recycling of plastics that fits into a circular bioeconomy. Finally, we discuss future applications for sustainable plastics with the aim to achieve the SDGs through international cooperation. <br /> Leading-edge polymer-based materials for consumer and advanced applications are necessary to achieve sustainable development at a global scale. It is essential to understand how sustainability can be incorporated in these materials via green chemistry, the integration of bio-based building blocks from biorefineries, circular bioeconomy strategies, and combined smart and functional capabilities.
KW  - biomaterial
KW  - degradable
KW  - functional
KW  - life cycle assessment
KW  - renewable
KW  - sustainability
Y1  - 2022
U6  - https://doi.org/10.1557/s43581-021-00015-7
SN  - 2329-2229
SN  - 2329-2237
VL  - 9
IS  - 1
SP  - 28
EP  - 34
PB  - Springer Nature
CY  - London
ER  - 
TY  - JOUR
A1  - Folikumah, Makafui Y.
A1  - Behl, Marc
A1  - Lendlein, Andreas
T1  - Reaction behaviour of peptide-based single thiol-thioesters exchange reaction substrate in the presence of externally added thiols
JF  - MRS communications / a publication of the Materials Research Society
N2  - Identification of patterns in chemical reaction pathways aids in the effective design of molecules for specific applications. Here, we report on model reactions with a water-soluble single thiol-thioester exchange (TTE) reaction substrate, which was designed taking in view biological and medical applications. This substrate consists of the thio-depsipeptide, Ac-Pro-Leu-Gly-SLeu-Leu-Gly-NEtSH (TDP) and does not yield foul-smelling thiol exchange products when compared with aromatic thiol containing single TTE substrates. TDP generates an alpha,omega-dithiol crosslinker in situ in a 'pseudo intramolecular' TTE. Competitive intermolecular TTE of TDP with externally added "basic" thiols increased the crosslinker concentration whilst "acidic" thiols decreased its concentration. TDP could potentially enable in situ bioconjugation and crosslinking applications.
KW  - Biomaterials
KW  - Biomimetic
KW  - Mass spectrometry
KW  - Nuclear magnetic resonance
KW  - (NMR)
Y1  - 2021
U6  - https://doi.org/10.1557/s43579-021-00041-z
SN  - 2159-6859
SN  - 2159-6867
VL  - 11
IS  - 4
SP  - 402
EP  - 410
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Heydenreich, Matthias
A1  - Shainyan, Bagrat A.
T1  - At the experimental limit of the NMR conformational analysis
BT  - Si-29 and C-13 NMR study of the conformational equilibrium of 1-phenyl-1-tert-butylsilacyclohexane
JF  - Organic letters
N2  - The low temperature (95 K) NMR study of 1-Ph-1-t-Bu-silacyclohexane (1) showed the conformational equilibrium to be extremely one-sided toward thePh(ax),t-Bueq conformer. The barrier to interconversion has been measured (4.2-4.6 kcal/mol) and the conformational equilibrium [Delta nu = 1990.64 ppm (Si-29), 618.9 ppm (C-13), 1-Ph-ax:1-Pheq = (95.6-96.6%):(3.4-4.4%), K = 25 +/- 3, Delta G degrees = -RT ln K = 0.58-0.63 kcal/mol] analyzed. The assignment and quantification of the NMR signals is supported by MP2 and DFT calculations.
Y1  - 2021
U6  - https://doi.org/10.1021/acs.orglett.0c03878
SN  - 1523-7060
SN  - 1523-7052
VL  - 23
IS  - 2
SP  - 405
EP  - 409
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Mullan, Thomas
A1  - Maschio, Lorenzo
A1  - Saalfrank, Peter
A1  - Usvyat, Denis
T1  - Reaction barriers on non-conducting surfaces beyond periodic local MP2
BT  - Diffusion of hydrogen on alpha-Al2O3 (0001) as a test case
JF  - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr
N2  - The quest for "chemical accuracy" is becoming more and more demanded in the field of structure and kinetics of molecules at solid surfaces. In this paper, as an example, we focus on the barrier for hydrogen diffusion on a alpha-Al2O3 (0001) surface, aiming for a couple cluster singles, doubles, and perturbative triples [CCSD(T)]-level benchmark. We employ the density functional theory (DFT) optimized minimum and transition state structures reported by Heiden, Usvyat, and Saalfrank [J. Phys. Chem. C 123, 6675 (2019)]. The barrier is first evaluated at the periodic Hartree-Fock and local Moller-Plesset second-order perturbation (MP2) level of theory. The possible sources of errors are then analyzed, which includes basis set incompleteness error, frozen core, density fitting, local approximation errors, as well as the MP2 method error. Using periodic and embedded fragment models, corrections to these errors are evaluated. In particular, two corrections are found to be non-negligible (both from the chemical accuracy perspective and at the scale of the barrier value of 0.72 eV): the correction to the frozen core-approximation of 0.06 eV and the CCSD(T) correction of 0.07 eV. Our correlated wave function results are compared to barriers obtained from DFT. Among the tested DFT functionals, the best performing for this barrier is B3LYP-D3.
Y1  - 2022
U6  - https://doi.org/10.1063/5.0082805
SN  - 0021-9606
SN  - 1089-7690
VL  - 156
IS  - 7
PB  - AIP Publishing
CY  - Melville
ER  - 
TY  - JOUR
A1  - Mawire, Phillip
A1  - Mozirandi, Winnie
A1  - Heydenreich, Matthias
A1  - Chi, Godloves Fru
A1  - Mukanganyama, Stanley
T1  - Isolation and antimicrobial activities of phytochemicals from Parinari curatellifolia (Chrysobalanaceae)
JF  - Advances in pharmacological and pharmaceutical sciences
N2  - The widespread use of antimicrobial agents to treat infectious diseases has led to the emergence of antibiotic resistant pathogens. Plants have played a central role in combating many ailments in humans, and Parinari curatellifolia has been used for medicinal purposes. Seven extracts from P. curatellifolia leaves were prepared using serial exhaustive extraction of nonpolar to polar solvents. The microbroth dilution method was used to evaluate antimicrobial bioactivities of extracts. Five of the extracts were significantly active against at least one test microbe. Mycobacterium smegmatis was the most susceptible to most extracts. The methanol and ethanol extracts were the most active against M. smegmatis with an MIC of 25 mu g/mL. The hexane extract was the most active against Candida krusei with an MIC of 25 mu g/mL. None of the extracts significantly inhibited growth of Klebsiella pneumoniae and Staphylococcus aureus. Active extracts were selected for fractionation and isolation of pure compounds using gradient elution column chromatography. TLC analyses was carried out for pooling fractions of similar profiles. A total of 43 pools were obtained from 428 fractions. Pools 7 and 10 were selected for further isolation of single compounds. Four compounds, Pc4963r, Pc4962w, Pc6978p, and Pc6978o, were isolated. Evaluation of antimicrobial activities of Pc4963r, Pc4962w, and Pc6978p showed that the compounds were most active against C. krusei with MFC values ranging from 50 to 100 mu g/mL. Only Pc6978p was shown to be pure. Using spectroscopic analyses, the structure of Pc6978p was determined to be beta-sitosterol. The antifungal effects of beta-sitosterol were evaluated against C. krusei in vitro and on fabrics. Results showed that beta-sitosterol reduced the growth of C. krusei attached to Mendy fabric by 83%. Therefore, P. curatellifolia can be a source of lead compounds for prospective development of novel antimicrobial agents. Further work needs to be done to improve the antifungal activity of the isolated compound using quantitative structure-activity relationships.
Y1  - 2021
U6  - https://doi.org/10.1155/2021/8842629
SN  - 2633-4682
SN  - 2633-4690
PB  - Hindawi
CY  - London
ER  - 
TY  - JOUR
A1  - Bekir, Marek
A1  - Jelken, Joachim
A1  - Jung, Se-Hyeong
A1  - Pich, Andrij
A1  - Pacholski, Claudia
A1  - Kopyshev, Alexey
A1  - Santer, Svetlana
T1  - Dual responsiveness of microgels induced by single light stimulus
JF  - Applied physics letters
N2  - We report on the multiple response of microgels triggered by a single optical stimulus. Under irradiation, the volume of the microgels is reversibly switched by more than 20 times. The irradiation initiates two different processes: photo-isomerization of the photo-sensitive surfactant, which forms a complex with the anionic microgel, rendering it photo-responsive; and local heating due to a thermo-plasmonic effect within the structured gold layer on which the microgel is deposited. The photo-responsivity is related to the reversible accommodation/release of the photo-sensitive surfactant depending on its photo-isomerization state, while the thermo-sensitivity is intrinsically built in. We show that under exposure to green light, the thermo-plasmonic effect generates a local hot spot in the gold layer, resulting in the shrinkage of the microgel. This process competes with the simultaneous photo-induced swelling. Depending on the position of the laser spot, the spatiotemporal control of reversible particle shrinking/swelling with a predefined extent on a per-second base can be implemented.
Y1  - 2021
U6  - https://doi.org/10.1063/5.0036376
SN  - 0003-6951
SN  - 1077-3118
VL  - 118
IS  - 9
PB  - American Institute of Physics
CY  - Melville
ER  -