TY - JOUR A1 - Kapernaum, Nadia A1 - Lange, Alyna A1 - Ebert, Max A1 - Grunwald, Marco A. A1 - Häge, Christian A1 - Marino, Sebastian A1 - Zens, Anna A1 - Taubert, Andreas A1 - Gießelmann, Frank A1 - Laschat, Sabine T1 - Current topics in ionic liquid crystals JF - ChemPlusChem N2 - Ionic liquid crystals (ILCs), that is, ionic liquids exhibiting mesomorphism, liquid crystalline phases, and anisotropic properties, have received intense attention in the past years. Among others, this is due to their special properties arising from the combination of properties stemming from ionic liquids and from liquid crystalline arrangements. Besides interesting fundamental aspects, ILCs have been claimed to have tremendous application potential that again arises from the combination of properties and architectures that are not accessible otherwise, or at least not accessible easily by other strategies. The current review highlights recent developments in ILC research, starting with some key fundamental aspects. Further subjects covered include the synthesis and variations of modern ILCs, including the specific tuning of their mesomorphic behavior. The review concludes with reflections on some applications that may be within reach for ILCs and finally highlights a few key challenges that must be overcome prior and during true commercialization of ILCs. KW - electrochemistry KW - ionic liquid crystals KW - mesogen mesophases KW - self-assembly KW - X-ray diffraction Y1 - 2021 U6 - https://doi.org/10.1002/cplu.202100397 SN - 2192-6506 VL - 87 IS - 1 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Mehr, Fatemeh Naderi A1 - Grigoriev, Dmitry A1 - Heaton, Rebecca A1 - Baptiste, Joshua A1 - Stace, Anthony J. A1 - Puretskiy, Nikolay A1 - Besley, Elena A1 - Böker, Alexander T1 - Self-assembly behavior of oppositely charged inverse bipatchy microcolloids JF - Small : nano micro N2 - A directed attractive interaction between predefined "patchy" sites on the surfaces of anisotropic microcolloids can provide them with the ability to self-assemble in a controlled manner to build target structures of increased complexity. An important step toward the controlled formation of a desired superstructure is to identify reversible electrostatic interactions between patches which allow them to align with one another. The formation of bipatchy particles with two oppositely charged patches fabricated using sandwich microcontact printing is reported. These particles spontaneously self-aggregate in solution, where a diversity of short and long chains of bipatchy particles with different shapes, such as branched, bent, and linear, are formed. Calculations show that chain formation is driven by a combination of attractive electrostatic interactions between oppositely charged patches and the charge-induced polarization of interacting particles. KW - electrostatic interactions KW - patchy particles KW - polyelectrolyte inks KW - sandwich microcontact printing KW - self-assembly Y1 - 2020 U6 - https://doi.org/10.1002/smll.202000442 SN - 1613-6810 SN - 1613-6829 VL - 16 IS - 14 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Wolff, Martin A1 - Schüler, Anja A1 - Gast, Klaus A1 - Seckler, Robert A1 - Evers, Andreas A1 - Pfeiffer-Marek, Stefania A1 - Kurz, Michael A1 - Nagel, Norbert A1 - Haack, Torsten A1 - Wagner, Michael A1 - Thalhammer, Anja T1 - Self-Assembly of Exendin-4-Derived Dual Peptide Agonists is Mediated by Acylation and Correlated to the Length of Conjugated Fatty Acyl Chains JF - Molecular pharmaceutics N2 - Dual glucagon-like peptide-1/glucagon receptor agonists have emerged as promising candidates for the treatment of diabetes and obesity. Issues of degradation sensitivity and rapid renal clearance are addressed, for example, by the conjugation of peptides to fatty acid chains, promoting reversible albumin binding. We use combined dynamic and static light scattering to directly measure the self-assembly of a set of dual peptide agonists based on the exendin-4 structure with varying fatty acid chain lengths in terms of apparent molecular mass and hydrodynamic radius (R-S). We use NMR spectroscopy to gain an insight into the molecular architecture of the assembly. We investigate conformational changes of the monomeric subunits resulting from peptide self-assembly and assembly stability as a function of the fatty acid chain length using circular dichroism and fluorescence spectroscopy. Our results demonstrate that self-assembly of the exendin-4-derived dual agonist peptides is essentially driven by hydrophobic interactions involving the conjugated acyl chains. The fatty acid chain length affects assembly equilibria and the assembly stability, although the peptide subunits in the assembly retain a dynamic secondary structure. The assembly architecture is characterized by juxtaposition of the fatty acyl side chains and a hydrophobic cluster of the peptide moiety. This cluster experiences local conformational changes in the assembly compared to the monomeric unit leading to a reduction in solvent exposure. The N-terminal half of the peptide and a C-terminal loop are not in contact with neighboring peptide subunits in the assemblies. Altogether, our study contributes to a thorough understanding of the association characteristics and the tendency toward self-assembly in response to lipidation. This is important not only to achieve the desired bioavailability but also with respect to the physical stability of peptide solutions. KW - dual GLP-1/glucagon receptor agonist KW - self-assembly KW - light scattering KW - molecular architecture KW - lipidation KW - exendin-4 Y1 - 2020 U6 - https://doi.org/10.1021/acs.molpharmaceut.9b01195 SN - 1543-8384 SN - 1543-8392 VL - 17 IS - 3 SP - 965 EP - 978 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Kochovski, Zdravko A1 - Chen, Guosong A1 - Yuan, Jiayin A1 - Lu, Yan T1 - Cryo-Electron microscopy for the study of self-assembled poly(ionic liquid) nanoparticles and protein supramolecular structures JF - Colloid and polymer science : official journal of the Kolloid-Gesellschaft N2 - Cryo-electron microscopy (cryo-EM) is a powerful structure determination technique that is well-suited to the study of protein and polymer self-assembly in solution. In contrast to conventional transmission electron microscopy (TEM) sample preparation, which often times involves drying and staining, the frozen-hydrated sample preparation allows the specimens to be kept and imaged in a state closest to their native one. Here, we give a short overview of the basic principles of Cryo-EM and review our results on applying it to the study of different protein and polymer self-assembled nanostructures. More specifically, we show how we have applied cryo-electron tomography (cryo-ET) to visualize the internal morphology of self-assembled poly(ionic liquid) nanoparticles and cryo-EM single particle analysis (SPA) to determine the three-dimensional (3D) structures of artificial protein microtubules. KW - self-assembly KW - poly(ionic liquid) nanoparticles KW - protein self-assembly KW - cryo-electron microscopy KW - single particle analysis KW - cryo-electron KW - tomography Y1 - 2020 U6 - https://doi.org/10.1007/s00396-020-04657-w SN - 0303-402X SN - 1435-1536 VL - 298 IS - 7 SP - 707 EP - 717 PB - Springer CY - New York ER - TY - JOUR A1 - Stanglmair, Christoph A1 - Neubrech, Frank A1 - Pacholski, Claudia T1 - Chemical routes to surface enhanced infrared absorption (SEIRA) substrates JF - Zeitschrift für physikalische Chemie : international journal of research in physical chemistry and chemical physics N2 - Bottom-up strategies for fabricating SEIRA substrates are presented. For this purpose, wet-chemically prepared gold nanoparticles are coated with a polystyrene shell and subsequently self-assembled into different nanostructures such as quasi-hexagonally ordered gold nanoparticle monolayers, double layers, and honeycomb structures. Furthermore elongated gold nanostructures are obtained by sintering of gold nanoparticle double layers. The optical properties of these different gold nanostructures are directly connected to their morphology and geometrical arrangement - leading to surface plasmon resonances from the visible to the infrared wavelength range. Finally, SEIRA enhancement factors are determined. Gold nanoparticle double layers show the best performance as SEIRA substrates. KW - bottom-up KW - gold nanoparticles KW - self-assembly KW - surface enhanced spectroscopy Y1 - 2018 U6 - https://doi.org/10.1515/zpch-2018-1132 SN - 0942-9352 VL - 232 IS - 9-11 SP - 1527 EP - 1539 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Noack, Sebastian A1 - Schanzenbach, Dirk A1 - Koetz, Joachim A1 - Schlaad, Helmut T1 - Polylactide-based amphiphilic block copolymers BT - Crystallization-Induced Self-Assembly and Stereocomplexation JF - Macromolecular rapid communications N2 - The aqueous self-assembly behavior of a series of poly(ethylene glycol)-poly(l-/d-lactide) block copolymers and corresponding stereocomplexes is examined by differential scanning calorimetry, dynamic light scattering, and transmission electron microscopy. Block copolymers assemble into spherical micelles and worm-like aggregates at room temperature, whereby the fraction of the latter seemingly increases with decreasing lactide weight fraction or hydrophobicity. The formation of the worm-like aggregates arises from the crystallization of the polylactide by which the spherical micelles become colloidally unstable and fuse epitaxically with other micelles. The self-assembly behavior of the stereocomplex aggregates is found to be different from that of the block copolymers, resulting in rather irregular-shaped clusters of spherical micelles and pearl-necklace-like structures. KW - crystallization KW - polylactide KW - self-assembly KW - stereocomplexation Y1 - 2018 U6 - https://doi.org/10.1002/marc.201800639 SN - 1022-1336 SN - 1521-3927 VL - 40 IS - 1 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Wolff, Martin A1 - Schüler, Anja A1 - Gast, Klaus A1 - Seckler, Robert A1 - Evers, Andreas A1 - Pfeiffer-Marek, Stefania A1 - Kurz, Michael A1 - Nagel, Norbert A1 - Haack, Torsten A1 - Wagner, Michael A1 - Thalhammer, Anja T1 - Self-Assembly of Exendin-4-Derived Dual Peptide Agonists is Mediated by Acylation and Correlated to the Length of Conjugated Fatty Acyl Chains JF - Molecular pharmaceutics N2 - Dual glucagon-like peptide-1/glucagon receptor agonists have emerged as promising candidates for the treatment of diabetes and obesity. Issues of degradation sensitivity and rapid renal clearance are addressed, for example, by the conjugation of peptides to fatty acid chains, promoting reversible albumin binding. We use combined dynamic and static light scattering to directly measure the self-assembly of a set of dual peptide agonists based on the exendin-4 structure with varying fatty acid chain lengths in terms of apparent molecular mass and hydrodynamic radius (R-S). We use NMR spectroscopy to gain an insight into the molecular architecture of the assembly. We investigate conformational changes of the monomeric subunits resulting from peptide self-assembly and assembly stability as a function of the fatty acid chain length using circular dichroism and fluorescence spectroscopy. Our results demonstrate that self-assembly of the exendin-4-derived dual agonist peptides is essentially driven by hydrophobic interactions involving the conjugated acyl chains. The fatty acid chain length affects assembly equilibria and the assembly stability, although the peptide subunits in the assembly retain a dynamic secondary structure. The assembly architecture is characterized by juxtaposition of the fatty acyl side chains and a hydrophobic cluster of the peptide moiety. This cluster experiences local conformational changes in the assembly compared to the monomeric unit leading to a reduction in solvent exposure. The N-terminal half of the peptide and a C-terminal loop are not in contact with neighboring peptide subunits in the assemblies. Altogether, our study contributes to a thorough understanding of the association characteristics and the tendency toward self-assembly in response to lipidation. This is important not only to achieve the desired bioavailability but also with respect to the physical stability of peptide solutions. KW - dual GLP-1/glucagon receptor agonist KW - self-assembly KW - light scattering KW - molecular architecture KW - lipidation KW - exendin-4 Y1 - 2020 U6 - https://doi.org/10.1021/acs.molpharmaceut.9b01195 SN - 1543-8384 VL - 17 IS - 3 SP - 965 EP - 978 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Holec, Jan A1 - Rybáček, Jiří A1 - Vacek, Jaroslav A1 - Karras, Manfred A1 - Bednárová, Lucie A1 - Budesinsky, Milos A1 - Slusna, Michaela A1 - Holy, Petr A1 - Schmidt, Bernd A1 - Stará, Irena G. A1 - Starý, Ivo T1 - Chirality-Controlled Self-Assembly of Amphiphilic Dibenzo[6]helicenes into Langmuir-Blodgett Thin Films JF - Chemistry - a European journal N2 - Racemic and highly enantioenriched 3-methoxycarbonyl, 3-carboxy, and 3-hydroxymethyl derivatives of dibenzo[6]helicene were prepared. The Langmuir layers of these helicenes were formed at the air-water interface and transferred onto solid substrates to afford Langmuir-Blodgett films, which were then studied by ambient atomic force microscopy and (chir)optical spectroscopy. Significant differences were found in the behaviour of the Langmuir layers as well as in the morphology, UV/Vis, electronic circular dichroism (ECD), and fluorescence spectra of the Langmuir-Blodgett thin films depending on the molecular chirality and nature of the polar group. The experimental results were supported by molecular dynamics simulations. KW - arenes KW - chirality KW - helical structures KW - Langmuir-Blodgett films KW - self-assembly Y1 - 2019 U6 - https://doi.org/10.1002/chem.201901695 SN - 0947-6539 SN - 1521-3765 VL - 25 IS - 49 SP - 11494 EP - 11502 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Zhang, Shuhao A1 - Bramski, Julia A1 - Tutus, Murat A1 - Pietruszka, Jörg A1 - Böker, Alexander A1 - Reinicke, Stefan T1 - A Biocatalytically Active Membrane Obtained from Immobilization of 2-Deoxy-D-ribose-5-phosphate Aldolase on a Porous Support JF - ACS applied materials & interfaces N2 - Aldol reactions play an important role in organic synthesis, as they belong to the class of highly beneficial C-C-linking reactions. Aldol-type reactions can be efficiently and stereoselectively catalyzed by the enzyme 2-deoxy-D-ribose-5-phosphate aldolase (DERA) to gain key intermediates for pharmaceuticals such as atorvastatin. The immobilization of DERA would open the opportunity for a continuous operation mode which gives access to an efficient, large-scale production of respective organic intermediates. In this contribution, we synthesize and utilize DERA/polymer conjugates for the generation and fixation of a DERA bearing thin film on a polymeric membrane support. The conjugation strongly increases the tolerance of the enzyme toward the industrial relevant substrate acetaldehyde while UV-cross-linkable groups along the conjugated polymer chains provide the opportunity for covalent binding to the support. First, we provide a thorough characterization of the conjugates followed by immobilization tests on representative, nonporous cycloolefinic copolymer supports. Finally, immobilization on the target supports constituted of polyacrylonitrile (PAN) membranes is performed, and the resulting enzymatically active membranes are implemented in a simple membrane module setup for the first assessment of biocatalytic performance in the continuous operation mode using the combination hexanal/acetaldehyde as the substrate. KW - 2-deoxy-D-ribose-5-phoshphate aldolase KW - enzyme immobilization KW - enzymatically active membrane KW - enzyme/polymer conjugate KW - self-assembly Y1 - 2019 U6 - https://doi.org/10.1021/acsami.9b12029 SN - 1944-8244 SN - 1944-8252 VL - 11 IS - 37 SP - 34441 EP - 34453 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Lange, Birger A1 - Wagner, Jürgen A1 - Zentel, Rudolf T1 - Fabrication of robust high-quality ORMOCER (R) inverse opals JF - Macromolecular rapid communications N2 - The nanostructuring of ORMOCER (R) to form inverse opals is described. For this purpose a polymer opal is used as a template and infiltrated with liquid ORMOCER (R). After photopolymerization of the resin the host opal is dissolved in tetrahydrofuran and an ORMOCER (R) inverse opal is obtained. It shows excellent periodicity (by SEM) and optical properties to reveal a high degree of face centered cubic order. This replication process leads to a nanostructured photonic crystal with the outstanding mechanical properties of ORMOCER (R) and high temperature stability up to 350 degrees C. KW - colloids KW - inverse opals KW - ORMOCER (R) KW - photonic crystal KW - self-assembly Y1 - 2006 U6 - https://doi.org/10.1002/marc.200600429 SN - 1022-1336 VL - 27 SP - 1746 EP - 1751 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Olejko, Lydia A1 - Cywinski, Piotr J. A1 - Bald, Ilko T1 - Ion-Selective formation of a guanine quadruplex on DNA origami structures JF - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition N2 - DNA origami nanostructures are a versatile tool that can be used to arrange functionalities with high local control to study molecular processes at a single-molecule level. Here, we demonstrate that DNA origami substrates can be used to suppress the formation of specific guanine (G) quadruplex structures from telomeric DNA. The folding of telomeres into G-quadruplex structures in the presence of monovalent cations (e.g. Na+ and K+) is currently used for the detection of K+ ions, however, with insufficient selectivity towards Na+. By means of FRET between two suitable dyes attached to the 3- and 5-ends of telomeric DNA we demonstrate that the formation of G-quadruplexes on DNA origami templates in the presence of sodium ions is suppressed due to steric hindrance. Hence, telomeric DNA attached to DNA origami structures represents a highly sensitive and selective detection tool for potassium ions even in the presence of high concentrations of sodium ions. KW - DNA nanotechnology KW - FRET KW - G-quadruplexes KW - nanostructures KW - self-assembly Y1 - 2015 U6 - https://doi.org/10.1002/anie.201409278 SN - 1433-7851 SN - 1521-3773 VL - 54 IS - 2 SP - 673 EP - 677 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Kedracki, Dawid A1 - Filippov, Sergey K. A1 - Gour, Nidhi A1 - Schlaad, Helmut A1 - Nardin, Corinne T1 - Formation of DNA-Copolymer Fibrils Through an Amyloid-Like Nucleation Polymerization Mechanism JF - Macromolecular rapid communications N2 - Conjugation of a hydrophobic poly(2-oxazoline) bearing tertiary amide groups along its backbone with a short single stranded nucleotide sequence results in an amphiphilic comb/graft copolymer, which organizes in fibrils upon direct dissolution in water. Supported by circular dichroism, atomic force microscopy, transmission electron microscopy, and scattering data, fibrils are formed through inter- and intramolecular hydrogen bonding between hydrogen accepting amide groups along the polymer backbone and hydrogen donating nucleic acid grafts leading to the formation of hollow tubes. KW - DNA copolymers KW - fibers KW - hydrogen bonding KW - nucleation polymerization KW - self-assembly Y1 - 2015 U6 - https://doi.org/10.1002/marc.201400728 SN - 1022-1336 SN - 1521-3927 VL - 36 IS - 8 SP - 768 EP - 773 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Brosnan, Sarah M. A1 - Schlaad, Helmut A1 - Antonietti, Markus T1 - Aqueous Self-Assembly of Purely Hydrophilic Block Copolymers into Giant Vesicles JF - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition N2 - Self-assembly of macromolecules is fundamental to life itself, and historically, these systems have been primitively mimicked by the development of amphiphilic systems, driven by the hydrophobic effect. Herein, we demonstrate that self-assembly of purely hydrophilic systems can be readily achieved with similar ease and success. We have synthesized double hydrophilic block copolymers from polysaccharides and poly(ethylene oxide) or poly(sarcosine) to yield high molar mass diblock copolymers through oxime chemistry. These hydrophilic materials can easily assemble into nanosized (<500nm) and microsized (>5m) polymeric vesicles depending on concentration and diblock composition. Because of the solely hydrophilic nature of these materials, we expect them to be extraordinarily water permeable systems that would be well suited for use as cellular mimics. KW - block copolymers KW - polymersomes KW - polysaccharides KW - self-assembly KW - vesicles Y1 - 2015 U6 - https://doi.org/10.1002/anie.201502100 SN - 1433-7851 SN - 1521-3773 VL - 54 IS - 33 SP - 9715 EP - 9718 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Weiss, Jan A1 - Wienk, Hans A1 - Boelens, Rolf A1 - Laschewsky, André T1 - Block copolymer micelles with an intermediate star-/flower-like structure studied by H-1 NMR relaxometry JF - Macromolecular chemistry and physics N2 - H-1 NMR relaxation is used to study the self-assembly of a double thermoresponsive diblock copolymer in dilute aqueous solution. Above the first transition temperature, at which aggregation into micellar structures is observed, the trimethylsilyl (TMS)-labeled end group attached to the shell-forming block shows a biphasic T-2 relaxation. The slow contribution reflects the TMS groups located at the periphery of the hydrophilic shell, in agreement with a star-like micelle. The fast T-2 contribution corresponds to the TMS groups, which fold back toward the hydrophobic core, reflecting a flower-like micelle. These results confirm the formation of block copolymer micelles of an intermediate nature (i.e., of partial flower-like and star-like character), in which a part of the TMS end groups folds back to the core due to hydrophobic interactions. KW - block copolymers KW - polymer micelles KW - relaxation NMR spectroscopy KW - self-assembly KW - thermoresponsive materials Y1 - 2014 U6 - https://doi.org/10.1002/macp.201300753 SN - 1022-1352 SN - 1521-3935 VL - 215 IS - 9 SP - 915 EP - 919 PB - Wiley-VCH CY - Weinheim ER -