? NIR-Tricarbocyanines in supramolecular platforms: sensor model systems derived from nanoparticles and dendrimers

MARIA EVA PICHEL; GUILLERMO MENENDEZ; CARLA C. SPAGNUOLO; ELIZABETH JARES-ERIJMAN

Córdoba

Encuentro; XI ELAFOT; 2012

Univ Nac Río Cuarto

Tricarbocyanines are clasified as NIR dyes because their absorption and emmission máxima are in the región 650-900 nm with extensive applications of this fluorophores in the specific labeling pf biomole-cules and as fluorescent sensors [1]. One of the advantage of working in the NIR región is that the cellular autofluorescence is negligible which make them excellent probes for fluorescence microscopy. In this work we present the synthesis of a biotinylated derivative (1) of a tricarbocyanine and the study of its optical properties as well as a model system based on the modification of the surface of fluorescent nanoparticles Quantum dots (QD). In this system, the Qd acts a the donor and the dye 1 as the acceptor of a FRET pair which undergoes a very efficient energy transfer, computed by means of steady-state and time resolved techniques. We also used a PAMAM dendrimer as a supramolecular platform for a sensor system and in this case we decorated the dendrimer with a tricarbocyanine derivative sensible to pH. The placement of many sensor units on a single supramolecular molecule renders an amplified signal for the detection enhancing sensi-bility and depressing detection limits. The results obtained within this study ensure the potentiality of this class of dyes for a wide field of studies from biomolecule labeling to fluorescent sensing.