TY - JOUR A1 - Felbeck, T. A1 - Mundinger, S. A1 - Lezhnina, M.M. A1 - Staniford, M. A1 - Resch-Genger, Ute A1 - Kynast, U.H. T1 - Multifold fluorescence enhancement in nanoscopic fluorophore-clay hybrids in transparent aqueous media JF - Chemistry - A European journal N2 - 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. KW - Biophotonics KW - Clay KW - Fluorescence KW - Hybrids KW - Nanoparticles PY - 2015 DO - https://doi.org/10.1002/chem.201406416 SN - 0947-6539 SN - 1521-3765 VL - 21 IS - 20 SP - 7582 EP - 7587 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-33816 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Felbeck, T. A1 - Lezhnina, M.M. A1 - Resch-Genger, Ute A1 - Kynast, U.H. T1 - Red emissive nanoclay hybrids in transparent aqueous dispersion-towards optical applications in biophotonics JF - Journal of luminescence N2 - Hydrophobic guest molecules like organic dyes and metal–ion complexes can be introduced into aqueous media via adsorption onto inorganic nanoclay host materials such as nm-sized laponite. Dispersions of these organic–inorganic hybrid materials show several advantageous properties like minimum light scattering due to their small size in the nanometer regime, ease of modification, low cost, low toxicity, and long-term stability, making them perfect candidates as signaling units and optically active materials in photonics and biotechnology. In this study, we summarize first findings on the easy-to-make, but chemically and optically fairly complex behavior of nanoclay hybrids for biotechnological applications. The latter includes the preparation of nanomaterials, which are colloidally stable in buffers and in the presence of biomolecules like proteins, and methods to control their surface chemistry. For this purpose, we used two red emitting fluorophores, the small organic dye Nile Red and the rare earth complex Eu(ttfa)3(topo)2, and evaluated the interaction of the red nanoclay hybrids with two model proteins, bovine serum albumin and β-lactoglobulin. We were able to monitor the formation of the protein corona around these hybrids using absorption and luminescence spectroscopy. KW - Nile Red KW - Europium complex KW - Protein corona KW - Nanoclay hybrids KW - Polarity probe PY - 2016 DO - https://doi.org/10.1016/j.jlumin.2014.11.039 SN - 0022-2313 SN - 1872-7883 VL - 169 SP - 728 EP - 732 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-33817 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -