Preparation and Application of Time-Resolved Fluorescent Nanospheres (TRFNs) for Immunochromatography of Ferritin

Time-resolved fluorescent nanospheres (TRFNs) are polymer nanospheres with special functional groups on the surface loaded with rare earth complexes which emit fluorescence when irradiated by ultraviolet light. TRFNs offer spherical morphology, homogeneity, good dispersity, large specific surface area, easy chemical modification, high loading capacity and good biocompatibility. The rare earth complexes possess unique properties that render them highly sensitive and capable of effectively excluding unspecific fluorescence. Hence, they constitute an excellent labeling material for the time-resolved fluorescence immunochromatographic assay (TRFIA). The developed method has a linear response to ferritin from 6 to 1000 ng/mL with a detection limit of 3.5 ng/mL, good reproducibility, and good accuracy compared with commercial chemiluminescence measurements of serum. These results suggest that the reported TRFN has utility for time-resolved fluorescence immunochromatographic assays.