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Int. J. Mol. Sci. 2012, 13(1), 1018-1028; doi:10.3390/ijms13011018
Article

Plasmonic Molecular Nanohybrids—Spectral Dependence of Fluorescence Quenching

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Received: 21 December 2011; in revised form: 11 January 2012 / Accepted: 13 January 2012 / Published: 18 January 2012
(This article belongs to the Special Issue From Molecules to Nanomaterials)
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Abstract: We demonstrate strong spectral dependence of the efficiency of fluorescence quenching in molecular systems composed of organic dyes and gold nanoparticles. In order to probe the coupling with metallic nanoparticles we use dyes with varied spectral overlap between the plasmon resonance and their absorption. Hybrid molecular structures were obtained via conjugation of metallic nanoparticles with the dyes using biotin-streptavidin linkage. For dyes featuring absorption above the plasmon excitation in gold nanoparticles, laser excitation induces minute changes in the fluorescence intensity and its lifetime for both conjugated and non-conjugated mixtures, which are the reference. In contrast, when the absorption of the dye overlaps with the plasmon resonance, the effect is quite dramatic, reaching 85% and 95% fluorescence quenching for non-conjugated and conjugated mixtures, respectively. The degree of fluorescence quenching strongly depends upon the concentration of metallic nanoparticles. Importantly, the origin of the fluorescence quenching is different in the case of the conjugated mixture, as evidenced by time-resolved fluorescence. For conjugated mixtures of dyes resonant with plasmon, excitation features two-exponential decay. This is in contrast to the single exponential decay measured for the off-resonant configuration. The results provide valuable insight into spectral dependence of the fluorescence quenching in molecular assemblies involving organic dyes and metallic nanoparticles.
Keywords: plasmon excitation; fluorescence; conjugation; gold nanoparticle; organic dye plasmon excitation; fluorescence; conjugation; gold nanoparticle; organic dye
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Olejnik, M.; Bujak, Ł.; Mackowski, S. Plasmonic Molecular Nanohybrids—Spectral Dependence of Fluorescence Quenching. Int. J. Mol. Sci. 2012, 13, 1018-1028.

AMA Style

Olejnik M, Bujak Ł, Mackowski S. Plasmonic Molecular Nanohybrids—Spectral Dependence of Fluorescence Quenching. International Journal of Molecular Sciences. 2012; 13(1):1018-1028.

Chicago/Turabian Style

Olejnik, Maria; Bujak, Łukasz; Mackowski, Sebastian. 2012. "Plasmonic Molecular Nanohybrids—Spectral Dependence of Fluorescence Quenching." Int. J. Mol. Sci. 13, no. 1: 1018-1028.



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