Multifold Fluorescence Enhancement in Nanoscopic Fluorophore–Clay Hybrids in Transparent Aqueous Media |
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| Authors: | Tom Felbeck Simon Mundinger Dr Marina M Lezhnina Mark Staniford Dr Ute Resch‐Genger Dr Ulrich H Kynast |
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| Institution: | 1. Münster University of Applied Sciences, Stegerwaldstr. 39, 48565 Steinfurt (Germany);2. Division 1.10 Biophotonics, Federal Institute for Materials Research and Testing (BAM), Richard‐Willstaetter‐Str. 11, 12489 Berlin (Germany) |
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| Abstract: | Valuable emissive properties of organic fluorophores have become indispensable analytical tools in biophotonics, but frequently suffer from low solubilities and radiationless deactivation in aqueous media, that is, in biological ambience as well. In this report, nanoscaled dye–clay hybrids based on laponite, Na0.7{(Li0.3Mg5.5)Si8O20(OH)4]}, are taken advantage of to solubilize neutral dyes, which are natively not encountered in water. Previously reported efficiency and solubility bottlenecks of such hybrids can to a large extent be overcome by comparably simple chemical measures, as demonstrated here for two prominent examples, the fluorescent dyes Nile Red and Coumarin 153. On controlled co‐adsorption of small bifunctional quaternary ammonium ions (Me3N+C2H5OH and Me3N+C2H5NH2) we observed an outright efficiency boost by an order of magnitude, and a 30‐fold brightness gain. Even at higher concentrations, transparency and stability of the hybrid dispersions are retained, rendering them useful for employment as optically functional nanoparticles in bioassays and beyond. |
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| Keywords: | biophotonics clay fluorescence hybrids nanoparticles |
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