title: Directional surface plasmon-coupled emission from a 3 nm green fluorescent protein monolayer.
abstract: High-sensitivity detection schemes are of great interest for a number of applications. Unfortunately, such schemes are usually high-cost. We demonstrate a low-cost approach to a high-sensitivity detection scheme based on surface plasmon-coupled emission (SPCE). The SPCE of a monomolecular layer of green fluorescent protein (GFP) is reported here. The protein was electrostatically attached to a thin, SiO(2)-protected silver film deposited on a quartz substrate. The visible, directional emission of GFP was observed at a sharp, well-defined angle of 47.5 degrees from the normal to the coupling prism, and the spectrum corresponded to that of GFP. The SPCE resulting from the reverse Kretschmann configuration showed a 12-fold enhancement over the free space fluorescence. The directional emission was 97% p-polarized. The directionality and high polarization can be coupled with the intrinsic spectral resolution of SPCE to be used in the design miniaturized spectrofluorometers. The observation of SPCE in the visible region of the spectrum from a monolayer of protein opens up new possibilities in protein-based sensing.
authors.affiliation: Department of Chemical and Biochemical Engineering, Center for Advanced Sensor Technology, University of Maryland at Baltimore County, 5200 Westland Blvd., Baltimore, 21227, USA.
authors.forename: Yordan
authors.initials: Y
authors.lastname: Kostov
authors.forename: Derek S
authors.initials: DS
authors.lastname: Smith
authors.forename: Leah
authors.initials: L
authors.lastname: Tolosa
authors.forename: Govind
authors.initials: G
authors.lastname: Rao
authors.forename: Ignacy
authors.initials: I
authors.lastname: Gryczynski
authors.forename: Zygmunt
authors.initials: Z
authors.lastname: Gryczynski
authors.forename: Joanna
authors.initials: J
authors.lastname: Malicka
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Lakowicz
mesh_terms: D001709:Biotechnology; D005453:Fluorescence; D049452:Green Fluorescent Proteins / Q000737:chemistry*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D012834:Silver; D020349:Surface Plasmon Resonance / Q000379:methods*; D013499:Surface Properties
chemical_list: D049452:Green Fluorescent Proteins; D012834:Silver