title: Enhanced fluorescent immunoassays on silver fractal-like structures.
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.
authors.affiliation: Department of Chemistry, The University of Texas at Tyler, 3900 University Boulevard, Tyler, Texas 75799, USA. tshtoyko@uttyler.edu
authors.forename: Tanya
authors.initials: T
authors.lastname: Shtoyko
authors.forename: Evgenia G
authors.initials: EG
authors.lastname: Matveeva
authors.forename: I-Fen
authors.initials: IF
authors.lastname: Chang
authors.forename: Zygmunt
authors.initials: Z
authors.lastname: Gryczynski
authors.forename: Ewa
authors.initials: E
authors.lastname: Goldys
authors.forename: Ignacy
authors.initials: I
authors.lastname: Gryczynski
mesh_terms: D005455:Fluorescent Antibody Technique / Q000379:methods*; D017709:Fractals; D012834:Silver / Q000737:chemistry*
chemical_list: D012834:Silver