title: Silver Fractal-like Structures for Metal-Enhanced Fluorescence: Enhanced Fluorescence Intensities and Increased Probe Photostabilities.
abstract: Substantial increases in fluorescence emission from fluorophore-protein-coated fractal-like silver structures have been observed. We review two methods for silver fractal structure preparation, which have been employed and studied. The first, a roughened silver electrode, typically yielded a 100-fold increase in fluorophore emission, and the second, silver fractal-like structures grown on glass between two silver electrodes, produced a ≈500-fold increase. In addition, significant increases in probe photostability were observed for probes coated on the silver fractal like structures. These results further serve to compliment our recent work on the effects of nobel metal particles with fluorophores, a relatively new phenomenon in fluorescence we have termed both "metal-enhanced fluorescence" [1] and "radiative decay engineering" [2,3]. These results are explained by the metallic surfaces modifying the radiative decay rate (Γ) of the fluorescent labels. We believe that this new silver-surface preparation, which results in ultrabright and photostable fluorophores, offers a new generic technology platform for increased fluorescence signal levels, with widespread potential applications to the analytical sciences, imaging, and medical diagnostics.
authors.affiliation: Center for Fluorescence Spectroscopy and Institute of Fluorescence, Medical Biotechnology Center, University of Maryland Biotechnology Institute, 725 West Lombard St, Baltimore, Maryland, 21201.
authors.forename: Chris D
authors.initials: CD
authors.lastname: Geddes
authors.affiliation: University of Maryland School of Medicine, Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, 725 West Lombard St, Baltimore, Maryland 21201.
authors.forename: Alexandr
authors.initials: A
authors.lastname: Parfenov
authors.affiliation: Department of Chemistry, Roberts Wesleyan College, 2301 Westside Drive, Rochester, New York.
authors.forename: David
authors.initials: D
authors.lastname: Roll
authors.affiliation: University of Maryland School of Medicine, Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, 725 West Lombard St, Baltimore, Maryland 21201.
authors.forename: Ignacy
authors.initials: I
authors.lastname: Gryczynski
authors.affiliation: University of Maryland School of Medicine, Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, 725 West Lombard St, Baltimore, Maryland 21201.
authors.forename: Joanna
authors.initials: J
authors.lastname: Malicka
authors.affiliation: University of Maryland School of Medicine, Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, 725 West Lombard St, Baltimore, Maryland 21201.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Lakowicz
keywords: Metal-enhanced fluorescence; fractal silver structures; increased photostabilities; radiative decay engineering