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Multifold Fluorescence Enhancement in Nanoscopic Fluorophore–Clay Hybrids in Transparent Aqueous Media
Author(s) -
Felbeck Tom,
Mundinger Simon,
Lezhnina Marina M.,
Staniford Mark,
ReschGenger Ute,
Kynast Ulrich H.
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201406416
Subject(s) - fluorescence , fluorophore , aqueous solution , solubility , materials science , chemical engineering , nile red , chemistry , nanoscopic scale , adsorption , biological imaging , photochemistry , nanotechnology , organic chemistry , optics , physics , engineering
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, Na 0.7 {(Li 0.3 Mg 5.5 )[Si 8 O 20 (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 (Me 3 N + C 2 H 5 OH and Me 3 N + C 2 H 5 NH 2 ) 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.