Occurrence of Förster Resonance Energy Transfer between Quantum Dots and Gold Nanoparticles in the Presence of a Biomolecule

Abstract

In this paper the interactions of gold nanoparticles (Au NPs) and bovin serum albumin–gold nanoconjugates (BSA–GNPs) with cadmium sulfide quantum dots (CdS QDs) are investigated by using steady-state and time-resolved spectroscopic techniques under physiological conditions (pH ∼ 7). From the analysis of the steady-state and time-resolved fluorescence quenching of CdS QDs in aqueous solution in the presence of BSA–GNPs it has been inferred that fluorescence resonance (Forster type) energy transfer (FRET) is primarily responsible for the quenching phenomenon. But in the presence of only Au NPs the fluorescence quenching of CdS NPs is primarily static in nature. Thus, it is apparent that, in the presence of BSA (in the case of the bionanoconjugate system), FRET becomes operative between CdS QDs and Au NPs present in the BSA–GNPs bionanoconjugate, whereas in the absence of this biomolecule direct contact between CdS and Au NPs facilitates the formation of ground-state complex. As shown from the high-resolutio...