Enhanced fluorescent immunoassays on silver fractal-like structures

Tanya Shtoyko, Evgenia G. Matveeva, I. Fen Chang, Zygmunt Gryczynski, Ewa Goldys, Ignacy Gryczynski

Research output: Contribution to journalArticle

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Abstract

Using the effect of the fluorescence enhancement in close proximity to metal nanostructures, we have been able to demonstrate ultrasensitive immunoassays suitable for the detection of biomarkers. Silver fractal-like structures have been grown by electrochemical reduction of silver on the surface of glass slides. A model immunoassay was performed on the slide surface with rabbit IgG (antigen) noncovalently immobilized on the slide, and rhodamine red-X-labeled antirabbit IgG conjugate was subsequently bound to the immobilized antigen. The fluorescence signal was measured from the glass-fractal's surface using a confocal microscope, and the images were compared to the images from the same surface not coated with fractals. Our results showed significant enhancement (more than 100-fold) of the signal detected on fractals compared to bare glass. We thus demonstrate that such fractal-like structures can assist in improving the signals from assays used in medical diagnostics, especially those for analytes with molecular weight under 100 kDa.

Original languageEnglish
Pages (from-to)1962-1966
Number of pages5
JournalAnalytical Chemistry
Volume80
Issue number6
DOIs
Publication statusPublished - 15 Mar 2008

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