Metal Enhanced fluorescence emission and Quenching protection effect with a host-guest Nanophotonic-supramolecular structure

ALICIA V. VEGLIA; A. GUILLERMO BRACAMONTE

JOURNAL OF NANOPHOTONICS

SPIE-SOC PHOTOPTICAL INSTRUMENTATION ENGINEERS

Año: 2018 vol. 12 p. 1 - 12

1934-2608

The functionalization of the nanoparticle?s surface is one method for tuning their overall properties to fit targeted applications. In this work, we are looking to develop a nanosensor based on the specific supramolecular interactions between ß-cyclodextrin nanocavities (ßCD) and organic molecules of biological interests using Metal-enhanced fluorescence effect (MEF) as detection signal. We grafted ßCD, a typical macrocyclic host molecule that interacts specifically with different organic molecules and changes their physical properties (such as their fluorescence emission intensity), on gold nanoparticles. To evaluate this nanosensor and the effect of the metallic core, we worked with a typical organic molecule, Rhodamine B (RhB) that has a strong association constant with ßCD (5700 M-1) and it is well known to be quenched in presence of cyclodextrins. The results show that by grafting ßCD on gold nanoparticles, it is possible to increase the sensivity of RhB detection by 70, 80, and 294 % when compared to solutions in 1) a phosphate buffer, 2) with ßCD and 3) with Au NPs, respectively.These results probe that the use of a supramolecular system attached to a metallic nanoparticle can interact specifically with a dye to enhance it?s fluorescence emission through the metal-enhanced fluorescence (MEF) effect. Moreover, this type of nano-system can overcome the quenching of the signal by the matrix, such in the case of Rhodamine B (RhB) with Cyclodextrins. Eventually, this concept could be extended to other dyes with different quenching effects. For this reason, this type of nanosensor system could be used in the future to protect and enhance the dye emission of fluorophores in different biological media.