TY - JOUR A1 - Meißner, T. A1 - Bergmann, R. A1 - Oswald, J. A1 - Rode, K. A1 - Stephan, H. A1 - Richter, W. A1 - Zänker, H. A1 - Kraus, Werner A1 - Emmerling, Franziska A1 - Reck, Günter T1 - Chitosan-encapsulated Keggin anion [Ti2W10PO40]7-.Synthesis, characterization and cellular uptake studies N2 - The Keggin type polyoxotungstate [Ti2W10PO40]7- forms stable associates with the biopolymer chitosan in the nanometer size range. The cluster compound crystallizes from aqueous solution as K4H3[Ti2W10PO40] · 15H2O having a tetragonal structure. Both, the cluster compound and the chitosan/[Ti2W10PO40] associates show a high hydrolytic stability at pH 7.4. The associates formed between the cluster anion [Ti2W10PO40]7- with the polyaminosaccharide chitosan have been characterized by photon correlation spectroscopy, scanning electron microscopy, filtration, centrifugation and zeta potential measurements. The size of the associates formed is in the range of ca. 5×101 to 5×102 nm. These particles have a defined stoichiometry with 5–6 cluster anions bound per molecule chitosan. The isoelectric point determined by zeta potential measurements was found for a cluster anion to chitosan molar ratio of 5.5, indicating the charge neutralization between protonated chitosan and [Ti2W10PO40]7- anions. Cellular uptake studies with [Ti2W10PO40]7- using tumor cell lines FaDu (human squamous carcinoma) and HT-29 (human adenocarcinoma) showed that the tungsten amount inside the cells is remarkably enhanced in the presence of chitosan. KW - Cluster compound KW - Keggin structure KW - Bipolymer KW - Chitosan PY - 2006 DO - https://doi.org/10.1007/s11243-006-0035-z SN - 0340-4285 SN - 1572-901X VL - 31 IS - 5 SP - 603 EP - 610 PB - Springer CY - Dordrecht AN - OPUS4-12568 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Poppenberg, J. A1 - Richter, S. A1 - Traulsen, C.H.-H. A1 - Darlatt, Erik A1 - Baytekin, B. A1 - Heinrich, T. A1 - Deutinger, P.M. A1 - Huth, K. A1 - Unger, Wolfgang A1 - Schalley, C.A. T1 - Programmable multilayers of nanometer-sized macrocycles on solid support and stimuli-controlled on-surface pseudorotaxane formation N2 - Mechanically interlocked molecules (MIMs) such as rotaxanes and catenanes are capable of mechanical motion on the nanoscale and are therefore promising prototypes for molecular machines in recent nanotechnology. However, most of the existing examples are isotropically distributed in solution, which prohibits concerted movement and with it the generation of macroscopic effects. Thus, arranging them in ordered arrays is of huge interest in recent research. We report the deposition of quite densely packed multilayers of tetralactam macrocycles on gold surfaces by metal-coordinated layer-by-layer self-assembly. Linear dichroism effects in angle-resolved NEXAFS spectra indicate a preferential orientation of the macrocycles. The sequence of the metal ions can be programmed by the use of different transition metal ions at each deposition step. Additionally, reversible on-surface pseudorotaxane formation was successfully realized by repeated uptake and release of axle molecules inside the macrocycles cavities. KW - ISO KW - Standard KW - Surface analysis KW - Imaging PY - 2013 DO - https://doi.org/10.1039/c3sc50558h SN - 2041-6520 SN - 2041-6539 VL - 4 SP - 3131 EP - 3139 PB - RSC CY - Cambridge AN - OPUS4-29049 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Poppenberg, J. A1 - Richter, S. A1 - Traulsen, Ch. H.-H. A1 - Darlatt, Erik A1 - Baytekin, B. A1 - Heinrich, Thomas A1 - Deutinger, P. M. A1 - Huth, K. A1 - Unger, Wolfgang A1 - Schalley, Ch. T1 - Programmable multilayers of nanometer-sized macrocycles on solid support and stimuli-controlled on-surface pseudorotaxane formation N2 - Mechanically interlocked molecules (MIMs) such as rotaxanes and catenanes are capable of mechanical motion on the nanoscale and are therefore promising prototypes for molecular machines in recent nanotechnology. However, most of the existing examples are isotropically distributed in solution, which prohibits concerted movement and with it the generation of macroscopic effects. Thus, arranging them in ordered arrays is of huge interest in recent research. We report the deposition of quite densely packed multilayers of tetralactam macrocycles on gold surfaces by metal-coordinated layer-by-layer self-assembly. Linear dichroism effects in angle-resolved NEXAFS spectra indicate a preferential orientation of the macrocycles. The sequence of the metal ions can be programmed by the use of different transition metal ions at each deposition step. Additionally, reversible on-surface pseudorotaxane formation was successfully realized by repeated uptake and release of axle molecules inside the macrocycles cavities. KW - NEXAFS KW - XPS KW - Supramolecular Chemistry KW - Multilayers KW - Pyridine KW - UV/Vis KW - Macrocycles KW - Pseudorotaxanes PY - 2013 DO - https://doi.org/10.1039/c3sc50558h VL - 4 IS - 8 SP - 3131 EP - 3139 AN - OPUS4-42668 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Schartel, Bernhard A1 - Richter, K. H. A1 - Böhning, Martin ED - Morgan, A. B. ED - Wilkie, C. A. ED - Nelson, G. L. T1 - Synergistic use of talc in halogen-free flame retarded polycarbonate/Acrylonitrile-butadiene-styrene blends N2 - Pyrolysis, flammability, fire behavior, melt viscosity, and gas diffusion of bisphenol A polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS) were investigated, with bisphenol A bis(diphenyl phosphate) (BDP), with 10 wt.% talc and with BDP in combination with 5, 10 and 20 wt.% talc, respectively. Compared to PC/ABS, PC/ABS + BDP results in an increased decomposition temperature of PC, a higher char yield, a significantly increased LOI, a V-0 classification in UL 94, a reduced peak heat release rate (pHRR), and a reduced total heat release (THR) in the cone calorimeter. This efficient flame retardancy is due to mechanisms in both the gas and condensed phases. PC/ABS + 10 wt.% talc shows a decrease in the PC decomposition temperature. The fire behavior is improved in part compared to PC/ABS, with an increased LOI and reduced pHRR. PC/ABS + BDP + 10 wt.% talc shows a strong synergism in LOI, a V-0 classification, and a decrease in pHRR, whereas THR is slightly increased compared to PC/ABS + BDP. Talc decreases the gas diffusion and enhances the flow limit for low shear rates, both of which influence the pyrolysis and flammability results. Further, talc improves the protection properties of the fire residues. Nevertheless it also partly suppresses flame inhibition and the charring effect of BDP. The synergism between BDP and talc in LOI is obtained even for low talc loadings in PC/ABS + BDP + talc, whereas for higher loadings saturation is observed. KW - Flame retardancy KW - PC/ABS KW - Aryl phosphate KW - Talc PY - 2012 SN - 978-0-8412-2780-4 DO - https://doi.org/10.1021/bk-2012-1118.ch002 N1 - Serientitel: ACS Symposium Series – Series title: ACS Symposium Series VL - 1118 IS - Chapter 2 SP - 15 EP - 36 PB - Oxford University Press AN - OPUS4-27563 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tannenberg, Robert A1 - Paul, Martin A1 - Röder, Bettina A1 - Gande, S. L. A1 - Sreeramulu, S. A1 - Saxena, K. A1 - Richter, C. A1 - Schwalbe, H. A1 - Swart, C. A1 - Weller, Michael G. T1 - Chemiluminescence biosensor for the determination of cardiac troponin I (cTnI) N2 - Cardiac troponin I (cTnI) is a crucial biomarker for diagnosing cardiac vascular diseases, including acute myocardial infarction (AMI). This study presents a proof-of-concept chemiluminescence-based immunosensor for rapid and accurate measurement of cTnI, with the potential for online monitoring. The immunosensor incorporates a flow cell design and a sensitive complementary metal-oxide-semiconductor (CMOS) camera for optical readout. A microfluidic setup was established to enable selective and quasi-online determination of cTnI within ten minutes. The sensor was tested with recombinant cTnI in phosphate buffer, demonstrating measurements in the concentration range of 2–25 µg/L, with a limit of detection (LoD) of 0.6 µg/L (23 pmol/L) achieved using the optimized system. The immunosensor exhibited high selectivity, as no cross-reactivity was observed with other recombinant proteins such as cTnT and cTnC at a concentration of 16 µg/L. Measurements with diluted blood plasma and serum yielded an LoD of 60 µg/L (2.4 nmol/L) and 70 µg/L (2.9 nmol/L), respectively. This biosensor offers a promising approach for the rapid and sensitive detection of cTnI, contributing to the diagnosis and management of acute myocardial infarction and other cardiac vascular diseases. N2 - Das kardiale Troponin I (cTnI) ist ein wichtiger Biomarker für die Diagnose von Herz-Kreislauf-Erkrankungen, einschließlich des akuten Myokardinfarkts (AMI). In dieser Studie wird ein auf Chemilumineszenz basierender Immunsensor für die schnelle und genaue Messung von cTnI vorgestellt, der das Potenzial für eine Online-Überwachung hat. Der Immunsensor besteht aus einer Durchflusszelle und einer empfindlichen CMOS-Kamera (Complementary Metal-Oxide-Semiconductor) zur optischen Detektion. Es wurde ein mikrofluidischer Aufbau entwickelt, der eine selektive und quasi Online-Bestimmung von cTnI innerhalb von zehn Minuten ermöglicht. Der Sensor wurde mit rekombinantem cTnI in Phosphatpuffer getestet und zeigte einen Messbereich von 2-25 µg/L, wobei mit dem optimierten System eine Nachweisgrenze (LoD) von 0,6 µg/L (23 pmol/L) erreicht wurde. Der Immunsensor zeigte eine hohe Selektivität, da keine Kreuzreaktivität mit anderen rekombinanten Proteinen wie cTnT und cTnC bei einer Konzentration von 16 µg/L beobachtet wurde. Messungen mit verdünntem Blutplasma und Serum ergaben einen LoD von 60 µg/L (2,4 nmol/L) bzw. 70 µg/L (2,9 nmol/L). Dieser Biosensor bietet einen vielversprechenden Ansatz für den schnellen und empfindlichen Nachweis von cTnI, der zur Diagnose und Behandlung des akuten Myokardinfarkts und anderer kardialer Gefäßerkrankungen beitragen kann. KW - Acute myocardial infarction KW - Heart attack KW - Emergency KW - Diagnosis KW - Cardiac troponin KW - Biomarker KW - Immunosensor KW - Biosensor KW - Chemiluminescence KW - Luminol KW - Peroxidase KW - Monoclonal antibodies KW - Flow injection immunoassay KW - Immunometric assay KW - Immunometric biosensor KW - Microfluidic system KW - Monolithic column KW - Online biosensor PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575471 DO - https://doi.org/10.3390/bios13040455 SN - 2079-6374 VL - 13 IS - 4 SP - 1 EP - 20 PB - MDPI CY - Basel AN - OPUS4-57547 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Traulsen, C. H.-H. A1 - Kunz, V. A1 - Heinrich, Thomas A1 - Richter, S. A1 - Holzweber, Markus A1 - Schulz, A. A1 - von Krbek, L. K. S. A1 - Scheuschner, U. T. J. A1 - Poppenberg, J. A1 - Unger, Wolfgang A1 - Schalley, C. A. T1 - Synthesis and coordinative layer-by-layer deposition of pyridine-functionalized gold nanoparticles and tetralactam macrocycles on silicon substrates N2 - Coordination chemistry was applied to deposit pyridine-functionalized gold nanoparticles on silicon substrates. The particles were synthesized through the Brust/Schiffrin route with a subsequent ligand exchange reaction yielding well-defined particles of two different sizes. Multilayer deposition was carried out on a pyridine-terminated SAM, anchored on a hydroxyl-terminated silicon surface. Analogously, Hunter/Vögtle-type tetralactam macrocycle multilayers were deposited as well as mixed layers containing both either in an alternating sequence or as a macrocycle multilayer with a terminating nanoparticle layer. These composite layers were examined with respect to their ability to bind squaraine axles in the macrocycle cavities. The amount of guest bound is higher for the composite layer with alternating macrocycles and nanoparticles. KW - Layer-by-layer deposition KW - Functionalized Au nanoparticles KW - SEM KW - TEM KW - DLS KW - XPS KW - NEXAFS KW - ToF-SIMS KW - IR KW - UV-vis PY - 2013 DO - https://doi.org/10.1021/la403222x SN - 0743-7463 SN - 1520-5827 VL - 29 IS - 46 SP - 14284 EP - 14292 PB - American Chemical Society CY - Washington, DC AN - OPUS4-29699 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hassler, J A1 - Matschat, Ralf A1 - Richter, Silke A1 - Barth, P. A1 - Detcheva, A.K. A1 - Waarlo, H.-J. T1 - Determination of 22 trace elements in high-purity copper including Se and Te by ETV-ICP OES using SF6, NF3, CF4 and H2 as chemical modifiers N2 - In supplementary work to the one published earlier, experiments with SF6, NF3, CF4 and H2 as new modifier gases for the matrix studied were performed. Our investigations were continued to improve the described analytical method and to achieve additional insights into the mechanism of analyte release. Our new survey is split in two parts. At first fluorinating modifiers were used to investigate the behaviour of a variety of trace elements (Ag, Al, As, Au, Bi, Cd, Co, Cr, Fe, Mg, Mn, Ni, P, Pb, Sb, Se, Si, Sn, Te, Ti, Zn and Zr). Most of them (exceptions Au, Se, and Te) could be effectively released from the copper matrix by thermo-halogenation reactions and by partial sub-sample evaporation. Using SF6 and NF3 as modifier gases, low limits of quantification (LOQs) were achieved for the 19 well released trace elements (typical ≤0.1 mg kg-1). Most elements (exceptions Ag, Mg, and Ni) could be calibrated by using aqueous calibration solutions without any sample pretreatment. For the trace determination of Se, Te, and Au, a further analytical method of ETV-ICP OES is described in the second part based on thermo-hydrogenation reactions by using a hydrogen/argon mixture as a modifier gas. The determination of Se and Te with very high analytical performance (LOQ < 0.1 mg kg-1) can either be carried out in a second analytical step succeeding the halogenation procedure, or the sub-sample is directly treated with H2 without previous halogenation procedure whereby the sub-sample can either be partially or totally evaporated. In this case some other analytes (Ag, Au, As, Bi, Cd, Fe, Mg, Ni, Pb, Sb, Sn, and Zn) can additionally be quantified simultaneously with Se and Te. KW - Pure Cu material KW - Electrothermal vaporization KW - Optical-emission spectrometry KW - Plasma-mass-spectrometry KW - Atomic-absorption spectrophotometry KW - Graphite-furnace AAS KW - Pure copper KW - Spectrochemical analysis KW - Precise determination KW - Sample introduction KW - Silicon-carbide PY - 2016 DO - https://doi.org/10.1039/C5JA00240K SN - 0267-9477 SN - 1364-5544 VL - 31 IS - 3 SP - 642 EP - 657 PB - Royal Society of Chemistry CY - London AN - OPUS4-35133 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -