title: Enhanced fluorescence of Cy5-labeled oligonucleotides near silver island films: a distance effect study using single molecule spectroscopy.
abstract: We investigated fluorescence enhancements and lifetime reductions of Cy5 probe molecules at various distances from the deposited silver island film surface using single molecule spectroscopic methods. The proximity of fluorophore molecules to the surface was controlled by alternating layers of biotinylated bovine serum albumin (BSA-biotin) and avidin, followed by binding of Cy5-labeled oligonucleotides to the top of a BSA-biotin layer structure. We observed dramatically varied brightness of fluorophores with distances from metal structures as well with reduced blinking in the presence of silver island films. In addition, distributions of fluorescence lifetimes and apparent emission intensities from individual molecules indicate an inhomogeneous nature of local matrix surface near metallic nanostructures. These studies illustrate the exclusive information that is otherwise hidden in ensemble measurements.
authors.affiliation: Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, Department of Biochemistry and Molecular Biology, Baltimore, Maryland 21201 USA. lakowicz@cfs.umbi.umd.edu
authors.forename: Yi
authors.initials: Y
authors.lastname: Fu
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Lakowicz
mesh_terms: D001665:Binding Sites; D019921:Biotinylation; D002232:Carbocyanines / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D009841:Oligonucleotides / Q000032:analysis* / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013997:Time Factors
chemical_list: D002232:Carbocyanines; D005456:Fluorescent Dyes; D009841:Oligonucleotides; C085321:cyanine dye 5; D012710:Serum Albumin, Bovine; D012834:Silver