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.
Lakowicz
Joseph R
JR
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
Malicka
Joanna
J
Huang
Jun
J
Gryczynski
Zygmunt
Z
Gryczynski
Ignacy
I
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