TY - JOUR A1 - Braun, Ulrike A1 - Lorenz, Edelgard A1 - Maskos, Michael T1 - Investigation of the durability of poly(ether urethane) in water and air N2 - In this study some relevant aspects of the durability of an aromatic poly(ether urethanes) was investigated. Hydrolytic and oxidative treatments at increased temperatures were applied. The induced changes in the materials under investigation were characterised by complementary polymer characterisation methods, such as ATR-FTIR, DSC and mechanical testing. The thermal and hydrolytic treatment did not significantly affect the chemical composition of the materials. Changes can be observed in the microstructure of the materials. PY - 2011 DO - https://doi.org/10.5301/IJAO.2011.6408 SN - 0391-3988 VL - 34 IS - 2 SP - 129 EP - 133 PB - Wichtig Ed. CY - Milano [u.a.] AN - OPUS4-23729 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Waltraut A1 - Koynov, K. A1 - Pierrat, S. A1 - Thiermann, Raphael A1 - Fischer, K. A1 - Maskos, Michael T1 - pH-change protective PB-b-PEO polymersomes N2 - Poly(butadiene)-b-poly(ethylene oxide) vesicles were successfully loaded with hydrophilic dye Phloxine B. Dye addition during vesicle formation leads to Phloxine B encapsulated inside the water filled vesicle core as well as to freely diffusing dye molecules. The removal of uncapsulated substrate involves time consuming methods like dialysis or harsher methods like ultra filtration or selective precipitation, posing the risk of irreversible sample manipulation. Here used Phloxine B as pH sensitive fluorescence indicator allows the characterization of hydrophilic loading without separation procedure by adjusting the pH value. Additionally membrane blocking efficiency can be studied by time dependent fluorescence measurements. Cryogenic TEM studies showed that the self-assembled structure remained unchanged when the hydrophilic dye was incorporated within the vesicles. Fluorescence microscopy imaging proved the encapsulation of the hydrophilic dye inside the core volume. The combination of fluorescence correlation spectroscopy (FCS) and dynamic light scattering (DLS) measurements as ensemble methods confirmed those results additionally. KW - Diblock copolymers KW - Self assembly KW - Vesicle loading PY - 2011 DO - https://doi.org/10.1016/j.polymer.2011.01.028 SN - 0032-3861 SN - 1873-2291 VL - 52 IS - 5 SP - 1263 EP - 1267 PB - Elsevier Ltd. AN - OPUS4-23520 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Maskos, Michael A1 - Berger, Georg A1 - Braun, Ulrike A1 - Heyn, Andreas A1 - Klinger, Christian A1 - Wachtendorf, Volker T1 - Schadensanalyse und Beständigkeit von Materialien in biomedizinischen Einsatzgebieten N2 - Der Anteil von Polymeren als Funktions- und Konstruktionswerkstoffe in dauerhaften medizinischen Anwendungen steigt beständig. Derartige Materialien müssen den mechanischen, biologischen und chemischen Bedingungen im Körper widerstehen (u.a. Abrieb, Hydrolyse, Degradation) und gleichzeitig gut verträglich sein. Der sichere Einsatz von polymeren Materialien erfordert die Kenntnisse über ihre Langzeitstabilität unter verschiedenen äußeren Bedingungen. Diese sind nicht nur beeinflusst durch die unmittelbare Umgebung in vivo, sondern auch durch die Historie der verwendeten Materialien. Dazu zählen u. a. erhöhte Temperaturen unter sauerstoffhaltiger Atmosphäre während der Verarbeitung oder die Exposition von ionisierender Strahlung oder reaktiven Radikalen während der Sterilisation. PY - 2011 SP - 83 EP - 85 CY - Berlin AN - OPUS4-23592 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Utech, S. A1 - Scherer, Christian A1 - Krohne, K. A1 - Carrella, L. A1 - Rentschler, E. A1 - Gasi, T. A1 - Ksenofontov, V. A1 - Felser, C. A1 - Maskos, Michael T1 - Magnetic polyorganosiloxane core-shell nanoparticles: Synthesis, characterization and magnetic fractionation N2 - Here, we present the synthesis, characterization and magnetic separation of magnetic polyorganosiloxane nanoparticles. Magnetic iron oxide nanoparticles with average particle radii of 3.2 nm had been synthesized by a simple coprecipitation process of iron(II) and iron(III) salt in basic solution. Afterwards, the particles were successfully incorporated into a polyorganosiloxane network via a polycondensation reaction of trimethoxymethylsilane (T), diethoxydimethylsilane (D) and the functional monomer (chloromethylphenyl)trimethoxysilane (ClBz-T) in aqueous dispersion. A core–shell system was chosen to increase the flexibility of the system concerning size, composition and functionalization possibilities. The magnetic nanocapsules with particle radii below 60 nm were separated from non-magnetic material with a high effectiveness by the use of commercially available separation columns which are commonly used for isolation of microbeads and subsequently characterized via transmission electron microscopy (TEM), asymmetrical flow field-flow fractionation (AF-FFF), superconducting quantum interference device (SQUID) and Mössbauer spectroscopy. KW - Nanoparticle KW - Magnetic KW - Encapsulation KW - Polyorganosiloxane KW - Magnetic separation PY - 2010 DO - https://doi.org/10.1016/j.jmmm.2010.06.056 SN - 0304-8853 VL - 322 IS - 21 SP - 3519 EP - 3526 PB - Elsevier CY - Amsterdam AN - OPUS4-22248 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tenzer, S. A1 - Docter, D. A1 - Rosfa, S. A1 - Wlodarski, A. A1 - Kuharev, J. A1 - Rekik, A. A1 - Knauer, S.K. A1 - Bantz, C. A1 - Nawroth, T. A1 - Bier, C. A1 - Sirirattanapan, J. A1 - Mann, W. A1 - Treuel, L. A1 - Zellner, R. A1 - Maskos, Michael A1 - Schild, H. A1 - Stauber, R.H. T1 - Nanoparticle size is a critical physico-chemical determinant of the human blood plasma corona: a comprehensive quantitative proteomic analysis N2 - In biological fluids, proteins associate with nanoparticles, leading to a protein 'corona' defining the biological identity of the particle. However, a comprehensive knowledge of particle-guided protein fingerprints and their dependence on nanomaterial properties is incomplete. We studied the long-lived ('hard') blood plasma derived corona on monodispersed amorphous silica nanoparticles differing in size (20, 30, and 100 nm). Employing label-free liquid chromatography mass spectrometry, one- and two-dimensional gel electrophoresis, and immunoblotting the composition of the protein corona was analyzed not only qualitatively but also quantitatively. Detected proteins were bioinformatically classified according to their physicochemical and biological properties. Binding of the 125 identified proteins did not simply reflect their relative abundance in the plasma but revealed an enrichment of specific lipoproteins as well as proteins involved in coagulation and the complement pathway. In contrast, immunoglobulins and acute phase response proteins displayed a lower affinity for the particles. Protein decoration of the negatively charged particles did not correlate with protein size or charge, demonstrating that electrostatic effects alone are not the major driving force regulating the nanoparticle–protein interaction. Remarkably, even differences in particle size of only 10 nm significantly determined the nanoparticle corona, although no clear correlation with particle surface volume, protein size, or charge was evident. Particle size quantitatively influenced the particle’s decoration with 37% of all identified proteins, including (patho)biologically relevant candidates. We demonstrate the complexity of the plasma corona and its still unresolved physicochemical regulation, which need to be considered in nanobioscience in the future. KW - Bionanoscience KW - Liquid chromatography mass spectrometry KW - Nanotoxicity KW - Nanomedicine KW - Immunology KW - Colloidal chemistry KW - Bioinformatics PY - 2011 DO - https://doi.org/10.1021/nn201950e SN - 1936-0851 VL - 5 IS - 9 SP - 7155 EP - 7167 PB - ACS Publ. CY - Washington, DC, USA AN - OPUS4-25167 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bleul, Regina A1 - Bachran, D. A1 - Thiermann, Raphael A1 - Bertin, Annabelle A1 - Fuchs, H. A1 - Maskos, Michael T1 - Probing polymersome-protein and -cell interactions: influence of different end-groups and environments N2 - Developing polymersomes for drug delivery purposes requires a deeper understanding of their behavior in physiological environment. We performed the self-assembly and in-situ loading of polybutadiene-block-polyethyleneoxide (PB-b-PEO) polymersomes in a continuous process using micromixers. Varying the length and end-groups of the starting block copolymer allows us to control the polymer membrane thickness and surface functionalities (hydroxyl or carboxylic acid), required to realize a further coupling with specific cell targeting ligands. To get a deeper understanding of these polymersomes in physiological environment, we studied the cellular response (HeLa cells) in presence of various polymersomes, and showed by cytotoxicity tests the relative biocompatibility of the systems. Flow cytometry experiments at 4?°C in PBS buffer showed a different behavior of hydroxyl-functionalized vesicles compared to carboxylic acid-functionalized vesicles. On the contrary cell binding in DMEM medium supplemented with 10% FCS was almost completely blocked with both kinds of polymersomes. Protein adsorption measurements by dynamic light scattering confirmed that protein binding occurs in all cases, which apparently influences the particle-cell interaction. This study contributes towards a deeper understanding of polymersomes in biological environment and further investigations will help us to design highly effective polymersomes for in vitro as well as in vivo applications. KW - Drug delivery KW - End-group functionality KW - Particle-cell interaction KW - Physiologic environment KW - Polymersomes KW - Protein adsorption PY - 2011 DO - https://doi.org/10.1002/masy.201100042 SN - 1022-1360 SN - 0258-0322 SN - 1521-3900 VL - 309/310 IS - 1 SP - 134 EP - 140 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-25246 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ruthard, C. A1 - Maskos, Michael A1 - Yildiz, H. A1 - Gröhn, F. T1 - Association of a cylindrical polyelectrolyte brush with tetravalent counterions N2 - Cylindrical poly(styrene sulfonate) brushes were combined with a tetravalent double-DABCO based counterion. With increasing addition of counterion, hydrodynamic radius and radius of gyration decrease and AFM reveals a conformation change from wormlike to curled structures. Rg/Rh changes from 1.3 to 0.9. Above charge stoichiometry, brushes become interconnected into finite size assemblies, which are stable in aqueous solution for charge ratios (ratio of the molar concentration of charged counterion groups to the molar concentration of charged monomer units of the polymer brush) 1 < Ι < 1.2. They are compact and consist of the brushes in curled (bent) conformation, which is in difference to network-like aggregates from cylindrical poly(styrene sulfonate) brushes with tetravalent porphyrin counterions (Gröhn et al. Macromolecules 2009) and to a wormlike — bent conformation — helix transition found for another brush counterion system (Müller et al. Soft Matter 2009). KW - Bottle-brush KW - Electrostatic interaction KW - Macromonomers KW - Polyelectrolytes KW - Self-assembly PY - 2011 DO - https://doi.org/10.1002/marc.201000622 SN - 1022-1336 SN - 1521-3927 VL - 32 IS - 6 SP - 523 EP - 527 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-25420 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Luty-Blocho, M. A1 - Fitzner, K. A1 - Hessel, V. A1 - Löb, P. A1 - Maskos, Michael A1 - Metzke, D. A1 - Paclawski, K. A1 - Wojnicki, M. T1 - Synthesis of gold nanoparticles in an interdigital micromixer using ascorbic acid and sodium borohydride as reducers N2 - Continuous-flow process conditions for the reduction to gold nanoparticles were varied following a variation scheme aiming at impacting each of the elementary steps–mixing, reaction, polymer diffusion and polymer binding. While the last three variations are done by proper material choice (reducer; polymeric stabilizer), flow processing using a multilamination micromixer intensified the mass transfer in all these steps and particularly improved the first mixing step of the reactants. As reducers L-ascorbic acid (H2Asc) and sodium borohydride (NaBH4) were used and as gold particle precursor chloroauric acid (HAuCl4). All processing runs were analysed by plasmon absorption and transmission electron microscopy to reveal size, shape and polydispersity. For the HAuCl4-H2Asc system, the smallest particles were 0.8–4 nm (7.5 mL/min) and 0.6–3 nm (10.0 mL/min) for the HAuCl4-NaBH4 system. This is at the upper edge of performance reported for batch systems in literature, i.e. among the smallest gold particles generated. While the particles made for the HAuCl4-H2Asc system were polydisperse and polyshaped for most process conditions (however being spherical and relatively uniform at the two largest flow rates investigated), processing with the HAuCl4-NaBH4 system resulted in particles sizes with small mean deviation and almost ideal spherical shape. With polyvinyl alcohol (PVA) as stabilizer, stable colloids were obtained for one week (violet coloured) up to at least 2 months (pink coloured) in case of reaction with ascorbic acid, and for at least 1 month in case of reaction with NaBH4. KW - Au nanoparticles KW - Kinetic of reduction reaction KW - Micromixer KW - Plasmon resonance PY - 2011 DO - https://doi.org/10.1016/j.cej.2011.03.104 SN - 1385-8947 SN - 0300-9467 SN - 0923-0467 SN - 0009-2487 VL - 171 IS - 1 SP - 279 EP - 290 PB - Elsevier CY - Amsterdam ; Boston, Mass. ; Jena ; London ; New York, NY ; Oxford ; Paris ; Philadelphia, PA ; San Diego, Calif. ; St. Louis, Mo. AN - OPUS4-25423 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ruthard, C. A1 - Maskos, Michael A1 - Kolb, U. A1 - Gröhn, F. T1 - Polystyrene sulfonate - porphyrin assemblies: influence of polyelectrolyte and porphyrin structure N2 - In this study, electrostatic self-assembly of different polystyrene sulfonates and a set of tetravalent cationic porphyrins is investigated. It is shown that association of linear polystyrene sulfonates of different molar masses yields finite size nanoscale assemblies that are stable in aqueous solution. Aggregates are compared to the ones of cylindrical brushes, revealing that both form assemblies in the 100 nm range with the charge ratio (molar ratio of porphyrin charges to polyelectrolyte charges) being determining, while the morphology of the resulting network-like assemblies is different for both polyelectrolyte architectures. For the smallest 8k polystyrene sulfonate, in addition, stoichiometric conditions differ. The influence of the molecular porphyrin structure was investigated by comparing meso-tetrakis(4-(trimethyl-ammonium)phenyl)porphyrin (TAPP) with its Cu(II) and Zn(II) loaded analogues and meso-tetrakis(4-N-methylpyridinium)porphyrin (TMPyP), revealing differences in stacking tendency and geometry. Additionally, the TMPyP accumulates more in the inside of the brush than the other porphyrins, likely due to the different position of its charged groups. The supramolecular nanostructures formed were characterized by UV–vis spectroscopy, light scattering, atomic force microscopy, cryo transmission electron microscopy, and small-angle neutron scattering. Results may build a valuable basis for the use of polyelectrolyte–porphyrin assemblies in medicine, catalysis, or energy conversion. KW - Polyelectrolyte KW - Porphyrin KW - Self-assembly KW - Supramolecular nanostructures PY - 2011 DO - https://doi.org/10.1021/jp1078357 SN - 1520-6106 SN - 1520-5207 SN - 1089-5647 VL - 115 IS - 19 SP - 5716 EP - 5729 PB - Soc. CY - Washington, DC AN - OPUS4-25424 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bléger, D. A1 - Liebig, T. A1 - Thiermann, Raphael A1 - Maskos, Michael A1 - Rabe, J.P. A1 - Hecht, S. T1 - Light-orchestrated macromolecular 'accordions': reversible photoinduced shrinking of rigid-rod polymers N2 - Lichtspiele: Lichteinstrahlung verursacht drastische Änderungen der Form stabförmiger Polymere mit Azobenzol‐Photochromen in der Hauptkette. Die eingebetteten Photoschalter wirken als molekulare Scharniere, die bei lichtinduzierter Isomerisierung zur reversiblen Schrumpfung und Streckung des Polymerrückgrats führen (siehe Schema); das System erinnert an ein lichtorchestriertes makromolekulares Akkordeon. N2 - Synthetic molecular systems undergoing structure and property changes as a response to external stimuli offer a series of relevant functions. Their direct use in solution, immobilized at surfaces, or integrated into adequate matrices, allow for the elaboration of nano-carriers, molecular electronic memory circuits, adaptive systems, artificial muscles, or healable materials, among others. Reversible systems are commonly generated by utilizing molecular switches as responsive bi-stable molecules. Of particular interest are switches controlled by non-invasive triggers, especially light, which can display high spatial and temporal resolution. Photoswitches were used to change properties, such as conductance and basicity, based on light-induced alteration of the molecular geometry, that is, their dimensions and shape. In nature, light-induced geometrical modifications of molecular systems lead to primary biological functions, such as the visual perception in vertebrates, or proton pumping in some bacteria, two examples that nicely illustrate the potential of photo-inducing structural modifications in organic systems. KW - Aggregation KW - Azoverbindungen KW - Nanostrukturen KW - Photochromie KW - Polymere PY - 2011 DO - https://doi.org/10.1002/ange.201106879 SN - 0044-8249 SN - 0932-2140 SN - 1521-3757 VL - 123 IS - 52 SP - 12767 EP - 12771 PB - Wiley-VCH CY - Weinheim AN - OPUS4-25394 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -