Molecular fluorescence enhancement on fractal-like structures.
In this report we discuss strong fluorescence enhancements on electrochemically grown silver nanostructures examined through fluorescence lifetime imaging microscopy (FLIM). Silver fractal-like nanostructures were deposited on three different substrates: glass, plastic, and silicon. For all of the surfaces the same dye was tested, DyLight 649, deposited in the form of a model immunoassay through excitation from a 635 nm pulsed solid-state laser. The brightness improvement in hot spots exceeded 300 fold, which is about two times higher than was observed previously on similar surfaces. The strongest enhancements correspond to the shortest lifetimes, indicating a strong interaction between excited molecules and silver nanostructures. Additionally, the photostability of the fluorescence dye was dramatically increased in the presence of electrochemically deposited silver nanostructures. The production of silver fractals is easy, very controllable, and can be applied to any surface. We therefore believe that silver fractal-like nanostructures can be used successfully in ultrasensitive assays and fluorophore trace detection.
Center for Commercialization of Fluorescence Technologies, UNTHSC, Fort Worth, Texas 76107, USA. Rafal.Luchowski@unthsc.edu
Rafal
R
Luchowski
Tanya
T
Shtoyko
Evgenia
E
Matveeva
Pabak
P
Sarkar
Julian
J
Borejdo
Zygmunt
Z
Gryczynski
Ignacy
I
Gryczynski
D055664:Electrochemical Techniques; D005456:Fluorescent Dyes / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D012834:Silver / Q000737:chemistry*
D005456:Fluorescent Dyes; D012834:Silver