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Issue 44, 2009
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The interaction between gold nanoparticles and cationic and anionic dyes: enhanced UV-visible absorption

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Abstract

The interactions of charge stabilised gold nanoparticles with cationic and anionic dyes are reported. The nanoparticles were synthesised by the Turkevich citrate reduction method. It was found that when a solution of thiazine dye is titrated against gold citrate hydrosol, at a critical concentration of dye there is an enhanced maximum absorption in the dye. The extinction coefficient is increased up to ten-fold. This enhancement was observed for a number of cationic thiazine dyes, of which methylene blue and toluidine blue are established light-activated antimicrobial agents. The same enhancement was not observed for anionic, acidic dyes such as rose bengal which showed no communication with the gold nanoparticles and showed UV-visible titration experiments with well formed isosbestic points. By studying the interaction of the dye and gold nanoparticles under conditions of different ionic strength and by using a zetasizer and TEM to measure the gold nanoparticle size it was demonstrated that the cause of enhancement was not due to nanoparticle aggregation. It is proposed that thiazine cationic dyes coordinate around a gold nanoparticle and give significantly enhanced UV-visible absorptions.

Graphical abstract: The interaction between gold nanoparticles and cationic and anionic dyes: enhanced UV-visible absorption

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Publication details

The article was received on 15 May 2009, accepted on 09 Sep 2009, published on 14 Oct 2009 and first published online on 14 Oct 2009


Article type: Paper
DOI: 10.1039/B909714G
Citation: Phys. Chem. Chem. Phys., 2009,11, 10513-10518
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    The interaction between gold nanoparticles and cationic and anionic dyes: enhanced UV-visible absorption

    N. Narband, M. Uppal, C. W. Dunnill, G. Hyett, M. Wilson and I. P. Parkin, Phys. Chem. Chem. Phys., 2009, 11, 10513
    DOI: 10.1039/B909714G

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