Increasing lanthanide luminescence by use of the RETEL effect

Leif, Robert C.; Vallarino, L. M.; Becker, Margie C.; Yang, Sean

doi:10.1002/cyto.a.20318

Cited by 13 publications

(17 citation statements)

References 18 publications

(32 reference statements)

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“…results from the use of closely spaced multiple fluorophores or lumiphores (compounds that luminesce) is minimized because the narrow emission band has minimal overlap with the excitation band (9). The third approach, time-delayed measurements, requires special instrumentation that records only photons emitted by long-lived lumiphores after illumination has stopped and the emission of short-lived fluorophores has decayed (1)(2)(3)6). Most luminescent labels based on inorganic elements have large Stokes' shifts as well as narrow emissions, and thus fulfill the first two of the above requirements.…”

Section: Review Of the Literaturementioning

confidence: 99%

“…Under these conditions localized luminescence could be observed, proving that the light-emitting Eu 31 ion of the EuMac had not been exchanged by the non-emitting Gd 31 or Y 31 ions. Fixed apoptotic (65) and S phase (6,66) cells, labeled with the EuMac conjugate of anti-5BrdU, could be imaged with a standard epifluorescence microscope under illumination at 365 nm with a standard Hg-Xe 100 watt arc lamp. Thus, effective imaging could be obtained without the previously needed expensive and complicated timegated or laser-based systems, or without heavy labeling of the anti-5BrdU.…”

Section: Increasing the Luminescence Of Lanthanide Complexes By Energmentioning

confidence: 99%

“…Finally, the use of relatively inexpensive instrumentation for time-delayed measurements, which eliminates the background fluorescence from the DAPI-DNA complex in the cell nucleus, permits the visualization and segmentation of lanthanide-labeled probes (6).…”

Section: Increasing the Luminescence Of Lanthanide Complexes By Energmentioning

confidence: 99%

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Increasing the luminescence of lanthanide complexes

et al. 2006

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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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Section: Review Of the Literaturementioning

confidence: 99%

Section: Increasing the Luminescence Of Lanthanide Complexes By Energmentioning

confidence: 99%

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Increasing the luminescence of lanthanide complexes

et al. 2006

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“…Lanthanide-based biolabels have been approved as an efficient, high-contrast method to suppress backgrounds using time-gate luminescence techniques (11,32). However, these have been only demonstrated broadly for cell bioimaging using europium-based bioprobes.…”

Section: Resultsmentioning

confidence: 99%

Demonstration of true‐color high‐contrast microorganism imaging for terbium bioprobes

Jin

2011

Cytometry Pt A

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Lanthanide bioprobes offer a number of novel advantages for advanced cytometry, including the microsecond luminescence lifetime, sharp spectral emission, and large stokes shift. However, to date, only the europium-based bioprobes have been broadly studied for time-gated luminescence cell imaging, though a wide range of efficient terbium bioprobes have been synthesized and some of them are commercially available. We analyze that the bottleneck problem was due to the lack of an efficient microscope with pulsed excitation at wavelengths of 300-330 nm. We investigate a recently available 315 nm ultraviolet (UV) light emitting diode to excite an epifluorescence microscope. Substituting a commercial UV objective (403), the 315 nm light efficiently delivered the excitation light onto the uncovered specimen. A novel pinhole-assisted optical chopper unit was attached behind the eyepiece for direct lifetime-gating to permit visual inspection of background-free images. We demonstrate the use of a commercial terbium complex for high-contrast imaging of an environmental pathogenic microorganism, Cryptosporidium parvum. As a result of effective autofluorescence suppression by a factor of 61.85 in the time domain, we achieved an enhanced signal-to-background ratio of 14.43. This type of time-gating optics is easily adaptable to the use of routine epifluorescence microscopes, which provides an opportunity for high-contrast imaging using multiplexed lanthanide bioprobes. ' International Society for Advancement of CytometryKey terms time-gated luminescence; bioimaging; terbium; UV LED; Cryptosporidium; high-contrast EPIFLUORESCENCE microscopes are routinely found in both research and diagnostic laboratories. From the practical point of view, cytometrists expect a microscope to be low cost, compact, easy-to-operate at high sensitivity, including the capacity to discriminate against nontarget substance, detect multiple species at once, and have high throughput. Time-domain discrimination of targeted microorganisms using long-lifetime lanthanide bioprobes shows promise in meeting these demands. This is due to the ease of time-gating of probes that have lifetimes of several hundreds of microseconds, which eliminates the autofluorescent background of several nanoseconds (1). In practice, however, there are several bottleneck problems challenging both the instrumentation and bioprobe developments. To date, only the europiumbased bioprobes (excited at 330-420 nm, emitting 615 nm at $10 nm bandwidth) have been broadly studied for time-gated luminescence cell imaging (1-15). This is due to the fact that other rare-earth ion complexes are either less efficient (16) [only europium and terbium complexes are less sensitive to vibrational quenching by energy transfer to OH, NH, or CH oscillators (15)] or require pulsed ultraviolet (UV) excitation below 330 nm (17). Another reason is the lack of near-infrared detection cameras. In fact, some cameras have included near-infrared blocking filters. For example, many efficient terbium-base...

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“…It is beneficial to have a bead that has the characteristics of the Europium Quantum Dye with its chemically defined emission peak and very small FWHM (4,21,34). The combination of the position of the peaks and the width of the histograms are parameters that can be used to determine if the spectroscopic system is working correctly.…”

Section: Calibration Test and The Far Red Regionmentioning

confidence: 99%