Title

Distance-Dependent Interactions Between Gold Nanoparticles And Fluorescent Molecules With Dna As Tunable Spacers

Abstract

Using stoichiometrically controlled 1:1 functionalization of gold nanoparticles with fluorescent dye molecules in which the dye molecule is held away from the particle surface by a rigid DNA spacer allows precise determination of the distance-dependent effect of the metal nanoparticles on fluorescence intensity. Two dyes were studied, Cy3 and Cy5, with two sizes of nanoparticles, 5 and 10nm. The larger the particle, the more quenching of the photoluminescence (PL) intensity, due to increased overlap of the dye's emission spectrum with the Au surface plasmon resonance. Fluorescence is quenched significantly for distances somewhat larger than the particle diameter, in good agreement with the predictions of an electrodynamics model based on interacting dipoles. The distance dependence of surface energy transfer behavior, i.e.quenching efficiency, is proportional to 1/d4, which involves no consideration of the size of the particle and the spectral overlap of the dye and AuNp. This surface energy transfer model is found qualitatively and agrees with the electrodynamic model, though the exponent is greater than 4 for the smaller nanoparticles (5nm), and smaller than 4 for the larger nanoparticles (10nm). © 2009 IOP Publishing Ltd.

Publication Date

11-25-2009

Publication Title

Nanotechnology

Volume

20

Issue

48

Number of Pages

-

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1088/0957-4484/20/48/485201

Socpus ID

70449806702 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/70449806702

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