Europium(III)-chelates embedded in nanoparticles are protected from interfering compounds present in assay media.
Publication/Presentation Date
2-28-2007
Abstract
Lanthanide chelates are excellent labels in ligand binding assays due to their long lifetime fluorescence, which enables efficient background reduction using time-resolved measurement. In separation-free homogeneous assays, however, some compounds in the sample may cause quenching of the lanthanide fluorescence and extra steps are required before these samples can be measured. In this study we have evaluated whether europium chelates packed inside a polystyrene nanoparticle are better protected from the environment than individual Eu(III)-chelates, and do these particles have higher tolerance against known interfering compounds (bivalent metal ions and variation of pH). We also tested whether metal ions had any effect on a fluorescence resonance energy transfer (FRET) based detection of a bioaffinity binding reaction. The presence of metal ions or variation of pH did not affect the fluorescence of the Eu(III)-chelate dyed nanoparticles, while significant decrease of the fluorescence was detected with a 9-dentate Eu(III)-chelate. Metal ions also decreased the fluorescence lifetime of the 9-dentate Eu(III)-chelate from 0.960 to 0.050 ms. Coloured metal ions caused a minor decrease in sensitised emission generated by FRET when Eu(III)-chelate dyed nanoparticles were used as donor labels. The decreased signal was due to the absorption of the sensitised emission by the coloured metal ions, since the metal ions had no effect on the lifetime of the sensitised emission. Thus the Eu(III)-chelate dyed nanoparticles are preferred labels in homogeneous bioaffinity assays, when interfering compounds are known to be present.
Volume
585
Issue
1
First Page
17
Last Page
23
ISSN
1873-4324
Published In/Presented At
Kokko, L., Lövgren, T., & Soukka, T. (2007). Europium(III)-chelates embedded in nanoparticles are protected from interfering compounds present in assay media. Analytica chimica acta, 585(1), 17–23. https://doi.org/10.1016/j.aca.2006.12.006
Disciplines
Medicine and Health Sciences
PubMedID
17386642
Department(s)
Department of Pathology and Laboratory Medicine
Document Type
Article