Fluorescence Quenching by Plasmonic Silver Nanoparticles

Abstract

Fluorescence quenching has various applications in proteins, membranes, and molecular biology. The quenching is used to determine the location of fluorophore in membranes. This chapter describes the mechanism involved in quenching effect of Plasmonic Silver (Ag) Nanoparticles (NPs). According to Forster's theory, the rate of energy transfer is based on the spectral overlap between emission spectrum of the fluorophore and absorption spectra of the Ag NPs, the relative orientation of the donor and acceptor transition dipoles, distance between the donor and acceptor transition dipoles, and fluorescence quantum yield of the donor. The degree of quenching depends on the structural details that control proximity between the fluorophore molecules and the Ag NPs core. The effect of Coulombic interactions on the energy transfer studied in two different ways. First, the Coulombic interactions between fluorophore and NPs depend on the charge densities of fluorophore and NPs. Second, they are based on the interaction within the dipole approximation.