Application of Eu(III) nanoparticle labels in time-resolved phosphorescence analysis for detection of thyroid stimulating hormone

Abstract

Eu(III) chelate-bonded polymer nanoparticles were used as phosphorescent labels to develop a highly sensitive phosphorescence analysis (PHOSPHAN^TM) for detection of human thyroid stimulating hormone (TSH). The phosphorescence was recorded in a time-resolved mode from microzones (microarrays) that were printed on the bottoms of the wells of standard polystyrene microplates. TSH was detected in paper discs (3.2 mm in diameter) that were punched from capillary blood that was dried on filter paper. The basic analytical and functional characteristics of this new method were similar to those of the commercial reagent kit for TSH detection in dried blood spots from newborns. Both methods made it possible to correctly detect the hormone concentration in the range of 0–250 μIU/mL blood. The analytical sensitivity of the Eu(III) nanoparticle label was 0.46 ± 0.1 μIU/mL (corresponded to approximately 17 fmol/L), which was comparable with the most sensitive assays. The matrix effect was insignificant. The coefficient of the variation of the results (up to 20%) was higher than in the commercial kit. This highly sensitive new test system could be integrated into PHOSPHAN-based multiplex tests to aid in simultaneous detection of markers for several congenital disorders in newborns.