title: Time-resolved fluorescence immunoassay for C-reactive protein using colloidal semiconducting nanoparticles.
abstract: Besides the typical short-lived fluorescence with decay times in the nanosecond range, colloidal II/VI semiconductor nanoparticles dispersed in buffer also possess a long-lived fluorescence component with decay times in the microsecond range. Here, the signal intensity of the long-lived luminescence at microsecond range is shown to increase 1,000-fold for CdTe nanoparticles in PBS buffer. This long-lived fluorescence can be conveniently employed for time-gated fluorescence detection, which allows for improved signal-to-noise ratio and thus the use of low concentrations of nanoparticles. The detection principle is demonstrated with a time-resolved fluorescence immunoassay for the detection of C-reactive protein (CRP) using CdSe-ZnS nanoparticles and green light excitation.
authors.affiliation: Laboratory of Biophysics, University of Turku, 20520 Turku, Finland. harri.harma@utu.fi
authors.forename: Harri
authors.initials: H
authors.lastname: Härmä
authors.forename: Juha
authors.initials: J
authors.lastname: Toivonen
authors.forename: Juhani T
authors.initials: JT
authors.lastname: Soini
authors.forename: Pekka
authors.initials: P
authors.lastname: Hänninen
authors.forename: Wolfgang J
authors.initials: WJ
authors.lastname: Parak
mesh_terms: D002097:C-Reactive Protein / Q000032:analysis*; D003102:Colloids; D005455:Fluorescent Antibody Technique / Q000379:methods*; D053758:Nanoparticles; D012666:Semiconductors
chemical_list: D003102:Colloids; D002097:C-Reactive Protein