Getting excited about lanthanide complexation chemistry

This review compares the chemical and physical properties of lanthanide ion complexes and of other narrow-emitting species that can be used as labels for cytometry. A series of luminescent lanthanide ion macrocyclic complexes, Quantum Dyes Ò , which do not release or exchange their central lanthanide ion, do accept energy transfer from ligands, and are capable of covalent binding to macromolecules, including proteins and nucleic acids, is described and their properties are discussed.Two methods are described for increasing the luminescence intensity of lanthanide ion complexes, which intrinsically is not as high as that of standard fluorophores or quantum dots. One method consists of adding a complex of a second lanthanide ion in a micellar solution (columinescence); the other method produces dry preparations by evaporation of a homogeneous solution containing an added complex of a second lanthanide ion or an excess of an unbound antenna ligand. Both methods involve the Resonance Energy Transfer Enhanced Luminescence, RETEL, effect as the mechanism for the luminescence enhancement. q 2006 International Society for Analytical Cytology Key terms: Quantum Dye; RETEL; lanthanide; macrocycle; luminescence; columinescence; time-delayed; europium; terbium Only one article published in Cytometry, by Seveus et al.(1), has described in detail the use of a lanthanide ion complex as a luminescent label for an antibody, and this article, published in 1992, dealt primarily with the instrumentation for time-gated microscopy. Thus, it is appropriate for a special issue of Cytometry to include a focused review of this class of luminescent labels. Extensive reviews of the clinical and other uses of lanthanide complexes have previously been published by Hemmil€ a and coworkers (2-4).This review presents a comparison of the spectral properties, relative sizes, and essential chemical features of lanthanide complexes and other narrow emitting labels. It also provides a critical description of two related approaches that can be used to overcome the comparatively low molar extinction coefficients (molar absorptivities) of lanthanide ion complexes: 1) the columinescence effect, where the luminescence of a lanthanide complex is increased in a micellar solution by energy transfer from a complex of a non-emitting lanthanide to a complex of an emitting lanthanide, and 2) the Resonance Energy Transfer Enhanced Luminescence, RETEL, effect (5) where the energy transfer occurs in the solid state.A companion Technical Note (6) describes the experimental aspects of the RETEL effect (5), which resulted in a major increase of the luminescence intensity of a specific type of lanthanide macrocycles, the Quantum Dyes Ò . This increase in luminescence facilitates the use of the Quantum Dyes as labels, either with fluorescent microscopes conventionally illuminated by a Mercury-Xenon (Hg-Xe) arc or-when it is helpful to eliminate contamination from the emissions of conventional fluorophoreswith new cost-effective time-gating instrumentation.The emissions...

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“…This provides a simple rationalization for the very long lifetimes, up to 2 ms, observed (40) for the luminescence of Ln 31 complexes.…”

Section: Comparison Of Quantum Dots Nanocrystalsmentioning

confidence: 71%

Increasing the luminescence of lanthanide complexes

et al. 2006

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“…To summarise, the main features that a lanthanide complex should possess in order to be suitable for use as a luminescent probe [16] in competitive biological media may be listed as follows: 1. High kinetic stability in the pH range 3 -10 of the 1:1, metal:ligand complex, i.e.…”

Section: Introductionmentioning

confidence: 99%

“…Considerations of points 1 and 2 suggests that the range of ligands that have been used to good effect for targeted 90 Y-radiotherapy [19] and in paramagnetic contrast agents for MRI (Gd) [16,20] are entirely appropriate for this purpose. Examples of such ligands include: firstly the poly-aminocarboxylates, dota 1 and dtpa 2 [16], their mono-or di-amides, 3 and 4 [21] or related mono-and di-substituted derivatives, e.g. 5 [22]; the tetra-phosphinates 6 [23] and their mono-substituted derivatives, e.g.…”

Section: Introductionmentioning

confidence: 99%

Luminescent lanthanide sensors for pH, pO2 and selected anions

Parker

2000

Coordination Chemistry Reviews

767

405

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“…Although this results in a much broader band than with the other trivalent lanthanides, it does mean that the transition has a reasonable molar absorption coefficient. 41,42 In certain cases, the inherent weakness of Ln(III) ion luminescence may be overcome by an energy transfer process, and interest in energy transfer in these systems has increased dramatically in the past few years [43][44][45][46][47] due to applications in luminescent assays in physics, chemistry, and biochemistry. For this phenomena, both dipole-dipole (Förster) 48 and exchange (Dexter) 49 mechanisms have been suggested for energy transfer involving lanthanide ions.…”

Section: Introductionmentioning

confidence: 99%

Changes in Hydration of Lanthanide Ions on Binding to DNA in Aqueous Solution

2005

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The interaction of the trivalent lanthanides Ce(III), Eu(III), and Tb(III) with sodium deoxyribonucleic acid (DNA) in aqueous solution has been studied using their luminescence spectra and decays. Complexation with DNA is indicated by changes in luminescence intensity. In the system terbium(III)-DNA, changes in luminescence with pH are suggested to be due to the protonation of phosphate groups. The degree of hydration of Tb(III) on binding to DNA is followed by luminescence lifetime measurements in water and deuterium oxide solutions, and it is found that the lanthanide ion loses at least one hydration water on binding to long double stranded DNA at pH 4.7 and pH 7. Rather different behavior is observed on binding to long or short single stranded DNA, where six water molecules are lost, independent of pH. It is suggested that in this case the lanthanide probably binds to the bases of the DNA backbone. The DNA conformation seems to be an important factor in the binding. In addition, the isotopic effect on terbium luminescence lifetime may provide a useful method to distinguish between single and double stranded DNA. DSC results are consistent with cleavage of the double helix of DNA at pH 9 in the presence of terbium.

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Getting excited about lanthanide complexation chemistry

Cited by 421 publications

References 68 publications

Increasing the luminescence of lanthanide complexes

Increasing the luminescence of lanthanide complexes

Luminescent lanthanide sensors for pH, pO2 and selected anions

Changes in Hydration of Lanthanide Ions on Binding to DNA in Aqueous Solution

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