Metal-enhanced fluoroimmunoassay on a silver film by vapor deposition

J Phys Chem B. 2005 Apr 28;109(16):7969-75. doi: 10.1021/jp0456842.

Abstract

We studied a fluoroimmunoassay using metal-enhanced fluorescence (MEF) detection on silver film generated by vapor deposition method. The morphology of the silver film was controlled through the thickness of the film. A silica layer was coated on the silver film to protect the film and separate the fluorophore from the metal surface. Rabbit immunoglobulin G (IgG) was adsorbed on the silica by physiosorption and then dye-labeled anti-rabbit IgG was bound to the immobilized rabbit IgG. It was observed that the fluorophore was quenched on a thin silver film (2 nm), enhanced on a thick film (>5 nm), and reached saturation (ca. 10 times enhancement) at 20 nm. The MEF was also dependent on the thickness of the silica with a maximum at 10 nm. The lowest lifetime was observed on the 20 nm silver film, which was consistent with the saturation of MEF. These results showed the properties of a silver film needed for a maximum increase of fluorescence intensity in a fluoroimmunoassay. Dependence of the MEF on the emission wavelength was also studied using different dye-labeled anti-rabbit IgGs.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Clinical Laboratory Techniques*
  • Fluoroimmunoassay
  • Microscopy, Atomic Force
  • Nanostructures
  • Silver*

Substances

  • Silver