Lanthanide chelate fluorescence lifetime

This comparison of the spectroscopic properties of the different types of fluorescent reporters underlines that semiconductor QDs and upconverting nanoparticles have no analogs in the field of organic dyes. Therefore, their unique features are unrivaled. The different molecular labels detailed here each display unique advantages that can compete with some of the favorable features of QDs and upconverting phosphors such as long lifetimes in the case of MLC systems and lanthanide chelates or very narrow emission bands for lanthanide chelates beneficial for spectral multiplexing. 

Metal complexes like lanthanide chelates (mainly europium or terbium), ruthenium phenanthrolines or bipyridyls, and platinum porphyrins can be used as fluorescent labels for biomolecules. Their long decay times are perfectly suited for a detection by time-resolved imaging, and the labeled target molecules can be used for the determination of intracellular recognition processes or for the screening of DNA and protein arrays. Ratiometric lifetime-based imaging methods in combination with sophisticated data acquisition and evaluation tools can substantially contribute to the development... 

Figure 2-17. Time-resolved fluorescence. Chelate complexes of many lanthanides show unusual fluorescence behaviour in that there is a large separation between the fluorescence excitation and emission maxima, and also extremely long fluorescence lifetimes. This enables...

The pulsed-source (time-resolved) method, then effects spectroscopic separation of the emission of several fluorescing species by taking advantage of differences in their decay times rather than their fluorescence intensities. This means that several overlapping fluorescences, such as those of free and antibody-bound ligand can be quantified simultaneously. Lanthanide chelate-labeled antibodies, which have long lifetimes (in the 1 = ms to 1 = ps range) form the basis of a time-resolved FIA, for which instrumentation is commercially available. 

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