| 11. |
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| 12. |
- Bäck, Marcus, et al.
(författare)
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Tyrosine Side-Chain Functionalities at Distinct Positions Determine the Chirooptical Properties and Supramolecular Structures of Pentameric Oligothiophenes
- 2020
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Ingår i: ChemistryOpen. - : Wiley. - 2191-1363. ; 9:11, s. 1100-1108
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Tidskriftsartikel (refereegranskat)abstract
- Control over the photophysical properties and molecular organization of pi-conjugated oligothiophenes is essential to their use in organic electronics. Herein we synthesized and characterized a variety of anionic pentameric oligothiophenes with different substitution patterns of L- or D-tyrosine at distinct positions along the thiophene backbone. Spectroscopic, microscopic, and theoretical studies of L- or D-tyrosine substituted pentameric oligothiophene conjugates revealed the formation of optically active pi-stacked self-assembled aggregates under acid conditions. The distinct photophysical characteristics, as well as the supramolecular structures of the assemblies, were highly influenced by the positioning of the L- or D-tyrosine moieties along the thiophene backbone. Overall, the obtained results clearly demonstrate how fundamental changes in the position of the enantiomeric side-chain functionalities greatly affect the optical properties as well as the architecture of the self-assembled supramolecular structures.
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| 13. |
- Choong, FX, et al.
(författare)
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Real-time optotracing of curli and cellulose in live Salmonella biofilms using luminescent oligothiophenes
- 2016
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Ingår i: NPJ biofilms and microbiomes. - : Springer Science and Business Media LLC. - 2055-5008. ; 2, s. 16024-
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Tidskriftsartikel (refereegranskat)abstract
- Extracellular matrix (ECM) is the protein- and polysaccharide-rich backbone of bacterial biofilms that provides a defensive barrier in clinical, environmental and industrial settings. Understanding the dynamics of biofilm formation in native environments has been hindered by a lack of research tools. Here we report a method for simultaneous, real-time, in situ detection and differentiation of the Salmonella ECM components curli and cellulose, using non-toxic, luminescent conjugated oligothiophenes (LCOs). These flexible conjugated polymers emit a conformation-dependent fluorescence spectrum, which we use to kinetically define extracellular appearance of curli fibres and cellulose polysaccharides during bacterial growth. The scope of this technique is demonstrated by defining biofilm morphotypes of Salmonella enterica serovars Enteritidis and Typhimurium, and their isogenic mutants in liquid culture and on solid media, and by visualising the ECM components in native biofilms. Our reported use of LCOs across a number of platforms, including intracellular cellulose production in eukaryotic cells and in infected tissues, demonstrates the versatility of this optotracing technology, and its ability to redefine biofilm research.
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| 14. |
- Choong, Ferdinand X., et al.
(författare)
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Nondestructive, real-time determination and visualization of cellulose, hemicellulose and lignin by luminescent oligothiophenes
- 2016
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Enabling technologies for efficient use of the bio-based feedstock are crucial to the replacement of oil-based products. We investigated the feasibility of luminescent conjugated oligothiophenes (LCOs) for non-destructive, rapid detection and quality assessment of lignocellulosic components in complex biomass matrices. A cationic pentameric oligothiophene denoted p-HTEA (pentamer hydrogen thiophene ethyl amine) showed unique binding affinities to cellulose, lignin, hemicelluloses, and cellulose nanofibrils in crystal, liquid and paper form. We exploited this finding using spectrofluorometric methods and fluorescence confocal laser scanning microscopy, for sensitive, simultaneous determination of the structural and compositional complexities of native lignocellulosic biomass. With exceptional photostability, p-HTEA is also demonstrated as a dynamic sensor for real-time monitoring of enzymatic cellulose degradation in cellulolysis. These results demonstrate the use of p-HTEA as a non-destructive tool for the determination of cellulose, hemicellulose and lignin in complex biomass matrices, thereby aiding in the optimization of biomass-converting technologies.
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| 15. |
- Choong, Ferdinand X., et al.
(författare)
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Stereochemical identification of glucans by oligothiophenes enables cellulose anatomical mapping in plant tissues
- 2018
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Efficient use of plant-derived materials requires enabling technologies for non-disruptive composition analysis. The ability to identify and spatially locate polysaccharides in native plant tissues is difficult but essential. Here, we develop an optical method for cellulose identification using the structure-responsive, heptameric oligothiophene h-FTAA as molecular fluorophore. Spectrophotometric analysis of h-FTAA interacting with closely related glucans revealed an exceptional specificity for beta-linked glucans. This optical, non-disruptive method for stereochemical differentiation of glycosidic linkages was next used for in situ composition analysis in plants. Multi-laser/multi-detector analysis developed herein revealed spatial localization of cellulose and structural cell wall features such as plasmodesmata and perforated sieve plates of the phloem. Simultaneous imaging of intrinsically fluorescent components revealed the spatial relationship between cell walls and other organelles, such as chloroplasts and lignified annular thickenings of the trachea, with precision at the sub-cellular scale. Our non-destructive method for cellulose identification lays the foundation for the emergence of anatomical maps of the chemical constituents in plant tissues. This rapid and versatile method will likely benefit the plant science research fields and may serve the biorefinery industry as reporter for feedstock optimization as well as in-line monitoring of cellulose reactions during standard operations.
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| 16. |
- Cieslar-Pobuda, Artur, et al.
(författare)
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Cell Type Related Differences in Staining with Pentameric Thiophene Derivatives
- 2014
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Ingår i: Cytometry Part A. - : John Wiley & Sons. - 1552-4922 .- 1552-4930. ; 85A:7, s. 628-635
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Tidskriftsartikel (refereegranskat)abstract
- Fluorescent compounds capable of staining cells selectively without affecting their viability are gaining importance in biology and medicine. Recently, a new family of optical dyes, denoted luminescent conjugated oligothiophenes (LCOs), has emerged as an interesting class of highly emissive molecules for studying various biological phenomena. Properly functionalized LCOs have been utilized for selective identification of disease-associated protein aggregates and for selective detection of distinct cells. Herein, we present data on differential staining of various cell types, including cancer cells. The differential staining observed with newly developed pentameric LCOs is attributed to distinct side chain functionalities along the thiophene backbone. Employing flow cytometry and fluorescence microscopy we examined a library of LCOs for stainability of a variety of cell lines. Among tested dyes we found promising candidates that showed strong or moderate capability to stain cells to different extent, depending on target cells. Hence, LCOs with diverse imidazole motifs along the thiophene backbone were identified as an interesting class of agents for staining of cancer cells, whereas LCOs with other amino acid side chains along the backbone showed a complete lack of staining for the cells included in the study. Furthermore, for p-HTMI,a LCO functionalized with methylated imidazole moieties, the staining was dependent on the p53 status of the cells, indicating that the molecular target for the dye is a cellular component regulated by p53. We foresee that functionalized LCOs will serve as a new class of optical ligands for fluorescent classification of cells and expand the toolbox of reagents for fluorescent live imaging of different cells.
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| 17. |
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| 18. |
- Johansson, Leif B. G., et al.
(författare)
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A variety of thiophene based ligands for detection of protein aggregates by surface plasmon resonance
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- By attaching an azide functional group via a tetraethylene glycol linker to the α-terminal position of a variety of oligothiophenes, thiophene-based ligands that can be utilized for detection of protein aggregates with surface plasmon resonance have been developed. All ligands displayed selectivity towards recombinant amyloid fibrils and the LCO/protein aggregate interaction could be detected by fluorescence as well as by surface plasmon resonance.
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| 19. |
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| 20. |
- Magnusson, Karin, et al.
(författare)
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An imidazole functionalized pentameric thiophene displays different staining patterns in normal and malignant cells
- 2015
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Ingår i: Frontiers in Chemistry. - : Frontiers Media S.A.. - 2296-2646. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- Molecular tools for fluorescent imaging of cells and their components are vital for understanding the function and activity of cells. Here, we report an imidazole functionalized pentameric oligothiophene, p-HTIm, that can be utilized for fluorescent imaging of cells. p-HTIm fluorescence in normal cells appeared in a peripheral punctate pattern partially co-localized with lysosomes, whereas a one-sided perinuclear Golgi associated localization of the dye was observed in malignant cells. The uptake of p-HTIm was temperature dependent and the intracellular target was reached within 1 h after staining. The ability of p-HTIm to stain cells was reduced when the imidazole side chain was chemically altered, verifying that specific imidazole side-chain functionalities are necessary for achieving the observed cellular staining. Our findings confirm that properly functionalized oligothiophenes can be utilized as fluorescent tools for vital staining of cells and that the selectivity towards distinct intracellular targets are highly dependent on the side-chain functionalities along the conjugated thiophene backbone.
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