ORGN 17 |
| Victor H. Perez-Luna and Kadir Aslan. Chemical and Environmental Engineering Department, Illinois Institute of Technology, 10 W.33rd street Perlstein Hall , Room127, Chicago, IL 60616 |
| Metallic nanoparticles can affect dramatically the emission characteristics of fluorophores located in their proximity. Here we exploit this strong influence in a system where gold nanoparticles are functionalized with biotin. Preparation of biotinylated gold nanoparticles is performed in the present of a nonionic surfactant to ensure their stability. The interaction of these biotinylated gold nanoparticles with AlexaTM488-labeled anti-biotin in solution was studied by optical absorption spectroscopy and fluorescence spectroscopy. It was found that reduction or enhancement of fluorescence emission could result when AlexaTM488-labeled anti-biotin interacted with biotinylated gold nanoparticles. This depended on the surface coverage of biotin groups, the concentration of antibody and the concentration of biotinylated gold nanoparticles. Introduction of soluble biotin to dissociate the bound antibodies from the surface of the nanoparticles reversed the signals observed previously. These observations can be explained in terms of the opposite effects that the metallic nanoparticles can have on the emission of fluorescence. One is quenching of fluorescence when the fluorophores are in close proximity to the metallic surfaces a second is the enhancement in the excitation intensity due to concentration of the excitation field in the vicinity of the nanoparticles. Finally, the metallic surfaces may also provide additional pathways for radiative decay of the fluorophores. These concepts will have important implications for novel materials in fluorescence detection. |
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Molecular Recognition and Self-Assembly
8:20 AM-12:00 PM, Sunday, September 7, 2003 Sheraton New York -- Imperial Ballroom B, Oral
Division of Organic Chemistry |