Development of Luminescent Terbium(III) Chelates for Protein Labelling: Effect of triplet‐state energy level

Abstract

The synthesis of novel Tb"' labels suitable for protein labelling are reported. Their luminescence properties as antibody conjugates were measured and compared to the results of corresponding Tb"' chelates of the parent ligand structures. When the lowest triplet-state energy level of the parent donor ligand was over 23 000 cm-I, i. e., the energy gap between the 5D, level of Tb"' and the lowest triplet-state energy level of the ligand exceeded 2600cm-', the label derivative with a long decay time (~=1.35-2.93 ms) and a high luminescence yield (E . 0 = 3 770-4 560) was found to be suitable for bioaffinity assays.Introduction. -Long-lifetime emitting lanthanide chelates as sensitive labels or probes, and time-resolved fluorometry in detection have already been used in a number of applications in bioaffinity assays [l].In commercial systems, due to the many requirements of optimal lanthanide chelate labels, compromises have been made, e.g., the detection comprises two separate steps, as a direct measurement of the analyte without any enhancement step is impossible [2]. In this respect, these technologies are not suitable for all applications, such as in situ hybridization, immunohistochemistry, homogeneous assays, and fluorescence imaging. In addition to sensitive bioaffinity assays, new highly luminescent and stable lanthanide labels permit the development of multilabel, miniaturized assay devices with simplified protocols and thus make it possible to perform multiparametric assays on sub-microliter volumes of samples. A lot of research effort has been directed to the design and synthesis of optimal labels also suitable for the applications mentioned above. The chelating agents commonly used for the sensitization of Eu"' and Tb"' ion luminescence include P-diketones

A new label technology for the detection of specific polymerase chain reaction products in a closed tube

“…This quenching is based on the environmentsensitive properties of the light absorbing moiety. It has been previously reported that the coupling of some lanthanide chelates to biomolecules, especially to proteins, has a profound effect on the decay time and thus on the quantum yield of the label (19). The probe has the simplest possible design since no extra secondary structures are needed.…”

New Luminescent Europium(III) Chelates for DNA Labeling

“…Anal. Calcd for C 31 (v) Synthesis of 4′-(biphenyl-4-yl)-2,2′:6′,2′′-terpyridine-6,6′′-bis(methanol) (5): A mixture of 400 mL dry ethanol, 7.02 g (14 mmol) of compound 4, and 3.02 g of NaBH 4 (80 mmol) was stirred at room temperature for 3 h and further refluxed for 1 h. After the solvent was evaporated, 200 mL of saturated NaHCO 3 was added, and the solution was heated to boiling. The cold mixture was filtered and washed with water (5.90 g, 92.0% yield).…”

Lanthanide Nanoparticules as Photoluminescent Reporters

“…Moreover, lanthanide From [89]; other spectral characteristics from [90] chelate incorporated into nanoparticle reporters can enable a sensitive, quadruple label technology for applications requiring multiplexing and are more versatile labels for bioanalytical assays than luminescent molecular lanthanide chelates [91]. Another advantage of particulate lanthanide reporters is that they are potentially insensitive to the environment [92] unlike some of the intrinsically luminescent molecular chelates, which respond to other molecules in their proximate environment [26,93]. Inorganic lanthanide-doped nanoparticles provide typically lower luminescence emission intensity compared to lanthanide-chelate dyed nanoparticles.…”

“…The second approach utilized the incorporation of luminescent rare earth metal chelates in polymeric particles coated with multiple antibodies [1]. Ultraviolet-excited inorganic lanthanide-doped phosphors [23] and conjugatable, intrinsically luminescent lanthanide chelates [24][25][26] were introduced later as an alternative approach for labeling with long-lifetime luminescent reporters. The lanthanide chelated-dyed particulate reporters, however, remained with little use in immunoassay applications until early 2000s, when their advantages were demonstrated again [27].…”