Heparin-Induced Dual Mode Luminescence Modulation of Organic Nanoparticles and Efficient Energy Transfer

Amphiphilic di-cationic fumaronitrile derivatives with peripheral n-alkyl chains formed organic nanoparticles (NPs) through self-assembly in aqueous media. The NPs exhibited enhanced luminescence in both steady-state and delayed mode in comparison to their molecularly dissolved state. Due to the presence of the multivalent array of positive charges on their surface, they were found to bind heparin, a bio-polyanion which is routinely employed during surgery as an anticoagulant. The electrostatically driven co-assemblies resulted in a significant enhancement in the steady-state and delayed luminescence of the NPs. This provided a highly sensitive detection of the polyanion in aqueous buffer as well as in highly competitive serum and plasma media. Furthermore, and most notably, the heparin based co-assemblies were found to act as efficient donors exhibiting fluorescence resonance energy transfer (FRET) to acceptor dyes with the energy transfer efficiency reaching up to 88%.