Distance-dependent interactions between gold nanoparticles and fluorescent molecules with DNA as tunable spacers

    Authors

    R. Chhabra; J. Sharma; H. N. Wang; S. L. Zou; S. Lin; H. Yan; S. Lindsay;Y. Liu

    Comments

    Authors: contact us about adding a copy of your work at STARS@ucf.edu

    Abbreviated Journal Title

    Nanotechnology

    Keywords

    METAL; SURFACE; OLIGONUCLEOTIDES; SENSORS; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied

    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 10 nm. 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/d(4), 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 ( 5 nm), and smaller than 4 for the larger nanoparticles ( 10 nm).

    Journal Title

    Nanotechnology

    Volume

    20

    Issue/Number

    48

    Publication Date

    1-1-2009

    Document Type

    Article

    Language

    English

    First Page

    10

    WOS Identifier

    WOS:000271471300001

    ISSN

    0957-4484

    Share

    COinS