title: Metal-Enhanced Fluorescence from Silver Nanowires with High Aspect Ratio on Glass Slides for Biosensing Applications.
abstract: High enhancement of fluorescence emission, improved fluorophore photostability, and significant reduction of fluorescence lifetimes have been obtained from high aspect ratio (>100) silver (Ag) nanowires. These quantities are found to depend on the surface loading of Ag nanowires on glass slides, where the enhancement of fluorescence emission increases with the density of nanowires. The surface loading dependence was attributed to the creation of intense electric fields around the network of Ag nanowires and to the coupling of fluorophore excited states that takes place efficiently at a distance of 10 nm from the surface of nanowires, which was confirmed by theoretical calculations. The enhancement of fluorescence emission of fluorescein isothiocyanate (FITC) was assessed by fluorescence spectroscopy and fluorescence-lifetime imaging microscopy (FLIM) to demonstrate the potential of high aspect ratio Ag nanowires. Fluorescence enhancement factors exceeding 14 were observed on Ag nanowires with high loading by FLIM. The photostability of FITC was the highest on nanowires with medium loading under continuous laser excitation for 10 min because of the significant reduction in the fluorescence lifetime of FITC on these surfaces. These results clearly demonstrate the potential of Ag nanowires in metal-enhanced fluorescence-based applications of biosensing on planar surfaces and cellular imaging.
authors.affiliation: Department of Chemistry, Morgan State University , 1700 East Cold Spring Lane, Baltimore, Maryland 21251, United States.
authors.forename: Biebele
authors.initials: B
authors.lastname: Abel
authors.affiliation: Department of Metallurgical and Materials Engineering, Middle East Technical University , Ankara 06800, Turkey.
authors.forename: Sahin
authors.initials: S
authors.lastname: Coskun
authors.affiliation: Department of Chemistry, Morgan State University , 1700 East Cold Spring Lane, Baltimore, Maryland 21251, United States.
authors.forename: Muzaffer
authors.initials: M
authors.lastname: Mohammed
authors.affiliation: Department of Chemistry, Morgan State University , 1700 East Cold Spring Lane, Baltimore, Maryland 21251, United States.
authors.forename: Richard
authors.initials: R
authors.lastname: Williams
authors.affiliation: Department of Metallurgical and Materials Engineering, Middle East Technical University , Ankara 06800, Turkey.
authors.forename: Husnu Emrah
authors.initials: HE
authors.lastname: Unalan
authors.affiliation: Department of Chemistry, Morgan State University , 1700 East Cold Spring Lane, Baltimore, Maryland 21251, United States.
authors.forename: Kadir
authors.initials: K
authors.lastname: Aslan