Tetracationic Bis-Triarylborane 1,3-Butadiyne as a Combined Fluorimetric and Raman Probe for Simultaneous and Selective Sensing of Various DNA,RNA, and Proteins |
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Authors: | Dr. Hashem Amini Dr. Željka Ban Matthias Ferger Sabine Lorenzen Florian Rauch Dr. Alexandra Friedrich Dr. Ivo Crnolatac Prof. Adriana Kenđel Prof. Snežana Miljanić Dr. Ivo Piantanida Prof. Dr. Todd B. Marder |
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Affiliation: | 1. Institut für Anorganische Chemie and, Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Würzburg, 97074 Germany;2. Laboratory for Study of Interactions of Biomacromolecules, Division of Organic Chemistry & Biochemistry, Ruđer Bošković Institute, Zagreb, HR-10000 Croatia;3. Division of Analytical Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, Zagreb, HR-10000 Croatia |
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Abstract: | A bis-triarylborane tetracation (4-Ar2B-3,5-Me2C6H2)-C≡C−C≡C-(3,5-Me2C6H2-4-BAr2 [Ar=(2,6-Me2-4-NMe3-C6H2)+] ( 24+ ) shows distinctly different behaviour in its fluorimetric response than that of our recently published bis-triarylborane 5-(4-Ar2B-3,5-Me2C6H2)-2,2′-(C4H2S)2–5′-(3,5-Me2C6H2-4-BAr2) ( 34+ ). Single-crystal X-ray diffraction data on the neutral bis-triarylborane precursor 2 N confirm its rod-like dumbbell structure, which is shown to be important for DNA/RNA targeting and also for BSA protein binding. Fluorimetric titrations with DNA/RNA/BSA revealed the very strong affinity of 24+ and indicated the importance of the properties of the linker connecting the two triarylboranes. Using the butadiyne rather than a bithiophene linker resulted in an opposite emission effect (quenching vs. enhancement), and 24+ bound to BSA 100 times stronger than 34+ . Moreover, 24+ interacted strongly with ss-RNA, and circular dichroism (CD) results suggest ss-RNA chain-wrapping around the rod-like bis-triarylborane dumbbell structure like a thread around a spindle, a very unusual mode of binding of ss-RNA with small molecules. Furthermore, 24+ yielded strong Raman/SERS signals, allowing DNA or protein detection at ca. 10 nm concentrations. The above observations, combined with low cytotoxicity, efficient human cell uptake and organelle-selective accumulation make such compounds intriguing novel lead structures for bio-oriented, dual fluorescence/Raman-based applications. |
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Keywords: | borane circular dichroism DNA/RNA sensor fluorescent probe protein sensor Raman probe |
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