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3. Tuning Interactions to Control Molecular Down Conversion in [2.2]Paracyclophane Bridged Oligo‐Tetracenes.

Author

Rapp, Mario R., Weiß, René, Wollny, Anna‐Sophie, Guldi, Dirk M., and Bettinger, Holger F.

Abstract

In tetracene, the energies of the lowest singlet excited state and twice that of the lowest triplet excited state are similar, allowing both down‐conversion (i.e., singlet fission, SF) and up‐conversion (i.e., triplet‐triplet annihilation up‐conversion, TTA‐UC) processes. Through‐space and through‐bond contributions to the inter‐tetracene coupling in purposefully designed oligomers play a crucial role in determining which of the two processes dominates. In this work, the focus is exclusively on SF in newly synthesized oligo‐tetracenes linked by conjugated [2.2]paracyclophane (PCP) building blocks. By choosing different PCP substitution patterns and by varying the degree of substitution the inter‐tetracene couplings are addressed. An independent variable is connecting the tetracences to the PCP at different positions to alter the through‐bond and through‐space coupling of the resulting oligo‐tetracenes. The novel oligo‐tetracenes are investigated by means of steady‐state and time‐resolved absorption and fluorescence spectroscopies with respect to the initial events of SF, that is, the transformation of a singlet excited state into a correlated triplet pair state. Briefly, through‐space couplings are profoundly weaker than through‐bond couplings that enable the correlated triplet pair state formation. If interactions are through‐space, correlated triplet pair state formation is turned off, while it is turned on if through‐bond interactions are operative. [ABSTRACT FROM AUTHOR]

Published
2024
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8. Infection with SARS-CoV-2 Is Associated with Elevated Levels of IP-10, MCP-1, and IL-13 in Sepsis Patients

Author

Eichhorn, Tanja, primary, Huber, Silke, additional, Weiss, René, additional, Ebeyer-Masotta, Marie, additional, Lauková, Lucia, additional, Emprechtinger, Robert, additional, Bellmann-Weiler, Rosa, additional, Lorenz, Ingo, additional, Martini, Judith, additional, Pirklbauer, Markus, additional, Orth-Höller, Dorothea, additional, Würzner, Reinhard, additional, and Weber, Viktoria, additional

Published
2023
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19. Analysis of Inflammatory Mediator Profiles in Sepsis Patients Reveals That Extracellular Histones Are Strongly Elevated in Nonsurvivors

Author

Eichhorn, Tanja, primary, Linsberger, Ingrid, additional, Lauková, Lucia, additional, Tripisciano, Carla, additional, Fendl, Birgit, additional, Weiss, René, additional, König, Franz, additional, Valicek, Gerhard, additional, Miestinger, Georg, additional, Hörmann, Christoph, additional, and Weber, Viktoria, additional

Published
2021
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35. Release and cellular origin of extracellular vesicles during circulation of whole blood over adsorbent polymers for lipid apheresis.

Author

Weiss, René, Eichhorn, Tanja, Spittler, Andreas, Mičušík, Matej, Fischer, Michael B., and Weber, Viktoria

Abstract

Whole blood lipid apheresis is clinically applied in patients with familial hypercholesterolemia to reduce low density lipoprotein and other apolipoprotein B 100 containing lipoproteins. Here, the hemocompatibility of two polyacrylate-coated polyacrylamide-based polymers for lipid apheresis by evaluating the adhesion of blood cells to the adsorbent polymers, their respective activation, as well as the release of microvesicles during circulation of whole blood over the polymers was studied. Characterization of the adsorbents by scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy revealed differences with respect to their surface morphology and their surface chemical composition. Despite these differences, equivalent amounts of leukocytes and platelets adhered to both polymers during circulation of whole blood over the adsorbent columns. The release of phosphatidylserine-exposing microvesicles, in contrast, increased significantly with increasing surface roughness and with the amount of polyacrylate groups at the adsorbent surface. The majority of microvesicles generated during blood-material contact were platelet-derived, and their release was associated with enhanced thrombin generation. Microvesicles were present in free and in cell-bound form, and 75% of all monocytes, but only 0.2% and 2.3% of red blood cells and platelets, respectively, were associated with microvesicles, pointing to a role of monocytes in the clearance of released microvesicles. Taken together, microvesicles are sensitive indicators for biomaterial-induced activation of blood cells in apheresis. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 636-646, 2017. [ABSTRACT FROM AUTHOR]

Published
2017
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37. Thrombocyte Adhesion and Release of ExtracellularMicrovesicles Correlate with Surface Morphology of Adsorbent Polymersfor Lipid Apheresis.

Author

Weiss, René, Spittler, Andreas, Schmitz, Gerd, Fischer, MichaelB., and Weber, Viktoria

Subjects
*BLOOD platelets, *CELL adhesion, *SURFACE morphology, *POLYMERS, *SORBENTS, *HEMAPHERESIS, *BLOOD lipids
Abstract

Wholeblood lipid apheresis is clinically applied to reduce lowdensity lipoprotein cholesterol in patients with homozygous familialhypercholesterolemia. Here, we studied the correlation between physicochemicalparameters, in particular, surface roughness and blood compatibility,of two polyacrylate-based and a dextran sulfate-based polymer forlipid apheresis. The adsorbent surface roughness was assessed by atomicforce microscopy. Freshly isolated human thrombocytes were circulatedover adsorbent columns downscaled equivalent to clinical use to studythrombocyte adhesion and microvesicle generation. Quantification ofthrombocytes and microvesicles in the flow-through of the columnsrevealed that both thrombocyte adhesion and microvesicle generationincreased with increasing adsorbent surface roughness. Activationof thrombocytes with thrombin receptor-activating peptide-6 favoredtheir adhesion to the adsorbents, as demonstrated by preferentialdepletion of CD62+and PAC-1+thrombocytes.Taken together, enhanced polymer surface roughness fostered cell adhesionand microvesicle release, underscoring the role of extracellular microvesiclesas markers of cellular activation and of blood compatibility. [ABSTRACT FROM AUTHOR]

Published
2014
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