title: Synthesis, characterization, and application of Eu(III), Tb(III), Sm(III), and Dy(III) lanthanide chelate nanoparticle labels.
abstract: Preparation and characterization of europium(III), terbium(III), samarium(III), and dysprosium(III) polystyrene nanoparticle labels with lanthanide-specific fluorescence properties has been presented. Emulsion copolymerization of styrene and acrylic acid was used to synthesize uniform-sized nanoparticles approximately 45 nm in diameter. Europium(III) and samarium(III) lanthanides were chelated with 2-naphthoyltrifluoroacetone and trioctylphosphine oxide to dye the spherical particles, whereas terbium(III) and dysprosium(III) chelate complexes contained a newly synthesized ligand, 4-(2,4,6-tridecyloxyphenyl)pyridine-2,6-dicarboxylic acid. The fluorescence properties of the four lanthanides-including a wide Stokes shift, a narrow emission peak, and long fluorescence lifetime-were retained despite the incorporation into the nanoparticles. Furthermore, the nanoparticles, containing more than 1000 lanthanide chelates, were detectable at label concentrations 3 orders of magnitude lower than the corresponding soluble lanthanide chelate labels. The applicability of the labels prepared was demonstrated by a heterogeneous sandwich-type immunoassay for human prostate-specific antigen, where the lowest limits of detection of 1.6, 2.4, 10.1, and 114.2 ng/L were achieved using europium(III), terbium(III), samarium(III), and dysprosium(III) nanoparticles, respectively. The spectral and functional properties of the lanthanide-embedded polystyrene nanoparticles developed here suggest that the technology is applicable for high-sensitivity multicolor assays.
authors.affiliation: Department of Biotechnology, University of Turku, Tykistökatu 6, FIN-20520 Turku, Finland.
authors.forename: Petri
authors.initials: P
authors.lastname: Huhtinen
authors.forename: Mirja
authors.initials: M
authors.lastname: Kivelä
authors.forename: Outi
authors.initials: O
authors.lastname: Kuronen
authors.forename: Virve
authors.initials: V
authors.lastname: Hagren
authors.forename: Harri
authors.initials: H
authors.lastname: Takalo
authors.forename: Heikki
authors.initials: H
authors.lastname: Tenhu
authors.forename: Timo
authors.initials: T
authors.lastname: Lövgren
authors.forename: Harri
authors.initials: H
authors.lastname: Härmä
mesh_terms: D002614:Chelating Agents / Q000737:chemistry; D004419:Dysprosium; D005063:Europium; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000379:methods; D028581:Lanthanoid Series Elements; D053758:Nanoparticles; D036103:Nanotechnology / Q000379:methods*; D017430:Prostate-Specific Antigen / Q000032:analysis; D012493:Samarium; D012680:Sensitivity and Specificity; D013725:Terbium
chemical_list: D002614:Chelating Agents; D005456:Fluorescent Dyes; D028581:Lanthanoid Series Elements; D013725:Terbium; D004419:Dysprosium; D012493:Samarium; D005063:Europium; D017430:Prostate-Specific Antigen