DEVELOPMENT OF LUMINESCENT LANTHANIDE CHELATE LABELS FOR DIAGNOSTIC ASSAYS

Luminescence properties of some of the lanthanide ions form the basis of highly sensitive diagnostic methods which employ their chelates as probes and time resolved fluorometry in the detection. In addition to bring highly luminescent, i.e., having an efficient light collection a nd energy transfer, photostability, good quantum yield and long excite d state lifetime, an ideal luminescent chelate label must be small and highly hydrophilic and contain a functional group enabling its gentle coupling to the bioreagent. Certain qualifications have to be fulfill ed when luminescent chelate labels are to be made, such as the optimal position of ligand triplet states, position and type of the binding a rm, insulation of the coupling group from the energy absorbing moiety, a critical distance between the luminescent moiety and protein surfac e (in case of Tb) and elimination of all possible quenching routes ass ociated with O-H and C-H stretching (in case of Eu). Lanthanide chelat es have already proven to be very useful in highly sensitive immunoass ays and simplified homogeneous assays. In addition, the new chelates d eveloped permit materialization of numerous future ideas, such as mini aturized assay devices able to perform multi-parametric assays on sub- microliter volumes of samples.