Ultrabright fluorescein-labeled antibodies near silver metallic surfaces.
Fluorescein-labeled antibodies are widely used in clinical assays and fluorescence microscopy. The fluorescent signal per labeled antibody is limited by fluorescein self-quenching, which occurs when the antibody is heavily labeled with multiple fluoresceins. We examined immunoglobulin G (IgG) when labeled with 0.7 to about 30 fluoresceins per antibody molecule. The extent of self-quenching was decreased, and the signal increased, when the labeled antibody was in close proximity to metallic silver particles. Time-resolved measurements showed that the intensity increase was due in part to a silver-induced increase in the radiative decay rate. These results suggest the use of labeled antibodies conjugated to silver particles as ultrabright probes for imaging or analytical applications.
Center for Fluorescence Spectroscopy, University of Maryland at Baltimore, Department of Biochemistry, 725 West Lombard Street, Baltimore, MD 21201, USA. lakowicz@cfs.umbi.umd.edu
Joseph R
JR
Lakowicz
Joanna
J
Malicka
Jun
J
Huang
Zygmunt
Z
Gryczynski
Ignacy
I
Gryczynski
D000906:Antibodies / Q000737:chemistry*; D019793:Fluorescein / Q000494:pharmacology*; D016650:Fluorescein-5-isothiocyanate / Q000737:chemistry; D005456:Fluorescent Dyes / Q000494:pharmacology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007074:Immunoglobulin G / Q000737:chemistry; D007202:Indicators and Reagents / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D015233:Models, Statistical; D012834:Silver / Q000737:chemistry*; D013053:Spectrophotometry; D013997:Time Factors
D000906:Antibodies; D005456:Fluorescent Dyes; D007074:Immunoglobulin G; D007202:Indicators and Reagents; D012834:Silver; D016650:Fluorescein-5-isothiocyanate; D019793:Fluorescein