Interactions between acridines and unimolecular micelles stemming from hyperbranched polyethyleneimine

A.S. PICCO; G.F. SILBESTRI; O. AZZARONI; M. CEOLIN

Buenos Aires

Congreso; International Gregorio Weber Conference; 2011

Gregorio Weber Comite

Hyperbranched polyethyleneimine (HPEI) was used to produce different reverse unimolecular micelles by capping the former with carboxylic acids of diverse chain lengths (C8, C10, C12, C14, C16, C18) via covalent linkage (amide bond). The derived products present core-shell structures resembling the behavior of polymolecular reverse micelles. The study of interactions between unimolecular micelles and fluorescent probes is a wide field of investigation nowdays. In this report we present some results on the interactions between different acridine derivatives (i.e. acridine yellow, acridine orange, acridine red, 9-amine acridine, among others) and different HPEI derived unimolecular micelles in organic media. The choice of the acridine family has two purposes: first, the acridines are cationic dyes with interesting properties, which are not the most common probes used to study this kind of unimicelles; second, the wide range of extinction and emission spectra covered by the selected derivatives allow us to study FRET inside the structures once the dyes are loaded. A systematic set of parameters like kinetics of phase transfer, behavior (spectra) in different solvents, anisotropy, effect of the chain length and FRET were evaluated. Also, the synthesized unimolecular micelles present a wide variety of supramolecular assemblies (observed using the SAXS technique) depending on solvent, temperature, and chain length, including structured aggregation and gelation, among others. The effect of these supramolecular changes over the fluorescence characteristics of the dyes was evaluated too.