Progress in Lanthanides as Luminescent Probes

Hemmilä, Ilkka; Laitala, Ville

doi:10.1007/s10895-005-2826-6

Cited by 437 publications

(306 citation statements)

References 145 publications

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“…This is probably an underestimate of the total increase, because with the present instrumentation there was a short lag before the zero time measurement was performed. The background due to the europium impurity in the Gd(TTFA) 3 was virtually undetectable. None of the subtractions used to produce the corrected images of the EuMac-Strept1Gd(TTFA) 3 disks had any negative pixels.…”

Section: Retel Experimental Resultsmentioning

confidence: 99%

“…The EuMac-Streptavidin (EuMac-Strept), EuMac-anti-5BrdU, and the gadolinium salt of the mononegative anion of thenoyltrifluoroacetone (Gd(TTFA) 3 ) were supplied by the Newport Instruments-Virginia Commonwealth University collaborative effort. The anti-5BrdU and HL60 S phase cells were supplied by Phoenix Flow Systems.…”

Section: Methodsmentioning

confidence: 99%

“…The anti-5BrdU and HL60 S phase cells were supplied by Phoenix Flow Systems. TBS Azide pH 7.4 (5) is an aqueous solution that contains in 1 l: 1.212 g of TRIS, 8.77 g of NaCl, and 0.50 g of NaN 3 . The pH of the solution was lowered by the addition of 1 M HCl.…”

Section: Methodsmentioning

confidence: 99%

“…The experiments were performed in duplicate to produce 2 sets of 4 wells containing respectively 18.2, 9.1, 4.5, and 2.3 pmols of EuMac-Strept. After the spots had dried, 10 lL of a 1 mM solution of Gd(TTFA) 3 was added to each of the 8 wells and one of the two sets of wells was covered with cellophane tape to prevent evaporation. It was noted that the presence of the cellophane tape decreased the emission by 10%.…”

Section: Methodsmentioning

confidence: 99%

“…The slide chamber was assembled by pressing a coverslip onto the double stick tape previously attached to a glass slide supporting the fiberglass disk. Ten lL of the Gd(TTFA) 3 solution was then applied slowly to the exposed edge of the fiberglass disk, which was allowed to dry slowly. The drying sample was imaged with a time-gated epifluorescence microscope (see below) using a 203 objective with a N.A.…”

Section: Methodsmentioning

confidence: 99%

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Increasing lanthanide luminescence by use of the RETEL effect

et al. 2006

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Background: Luminescent lanthanide complexes produce emissions with the narrowest-known width at half maximum; however, their significant use in cytometry required an increase in luminescence intensity. The companion review, Leif et al., Cytometry 2006;69A:767-778, described a new technique for the enhancement of lanthanide luminescence, the Resonance Energy Transfer Enhanced Luminescence (RETEL) effect, which increases luminescence and is compatible with standard slide microscopy. Methods: The luminescence of the europium ion macrocyclic complex, EuMac, was increased by employing the RETEL effect. After adding the nonluminescent gadolinium ion complex of the thenoyltrifluoroacetonate (TTFA) ligand or the sodium salt of TTFA in ethanol solution, the EuMac-labeled sample was allowed to dry. Both a conventional arc lamp and a time-gated UV LED served as light sources for microscopic imaging. The emission intensity was measured with a CCD camera. Multiple time-gated images were summed with special software to permit analysis and effective presentation of the final image.Results: With the RETEL effect, the luminescence of the EuMac-streptavidin conjugate increased at least six-fold upon drying. Nuclei of apoptotic cells were stained with DAPI and tailed with 5BrdUrd to which a EuMac-anti5BrdU conjugate was subsequently attached. Time-gated images showed the long-lived EuMac luminescence but did not show the short-lived DAPI fluorescence. Imaging of DNA-synthesizing cells with an arc lamp showed that both S phase and apoptotic cells were labeled, and that their labeling patterns were different. The images of the luminescent EuMac and fluorescent DAPI were combined to produce a color image on a white background. This combination of simple chemistry, instrumentation, and presentation should make possible the inexpensive use of the lanthanide macrocycles, Quantum Dyes Ò , as molecular diagnostics for cytological and histopathological microscopic imaging. q 2006 International Society for Analytical Cytology Key terms: quantum dye; columinescence; RETEL; lanthanide; macrocycle; luminescence; time-delayed; europium; terbium Lanthanide ion complexes have found a variety of significant applications in laboratory diagnostics (1-3); however, the weak luminescence of these complexes, which is due to their comparatively low molar extinction coefficients (molar absorptivities), was a major impediment to their use in cytometry (4). The problem of increasing the emission intensity of lanthanide ion complexes has been solved by the use of the resonance energy transfer enhanced luminescence (RETEL) effect, formerly called FRE-TEL (5), combined with measurement in the dry state. In the RETEL effect, as described by Leif, Vallarino, and coworkers in the companion Review article published in this issue of Cytometry (6), light energy originally absorbed by a nonluminescent photon acceptor (a complex or an unbound ligand) is transferred to the central lanthanide ion of a macrocyclic complex, Quantum Dye Ò , thus enhancing its emission int...

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Section: Retel Experimental Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Increasing lanthanide luminescence by use of the RETEL effect

et al. 2006

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Fluorescence in Organized Assemblies

Memon¹,

Balouch²,

Hinze³

2008

Encyclopedia of Analytical Chemistry

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This article provides an overview of the general properties of organized assembly (ordered media) systems, such as aqueous surfactant and bile salt micelles, lipid (liposomes) and surfactant vesicles, and cyclodextrins (CDs), and summarizes their utilization to enhance the performance of analytical fluorescence measurements. In many instances, organic molecules and metal complex species when included within a CD cavity or solubilized and bound to surfactant aggregates exhibit enhanced fluorescence, improving detectability of such analytes. The altered microenvironment within the organized medium can impede the interfering action of other species (inorganic or organic) present in the sample matrix, which often improves the selectivity of the analytical method. These benefits of improved sensitivity and selectivity arise from the compartmentalization, isolation, and shielding of the excited singlet state of the guest analyte from quenching and nonradiative decay processes, as well as preventing side reactions that otherwise can occur in bulk solution (or sample matrix). Organic solvents or time‐consuming extraction steps can also be avoided, owing to the increased solubility of nonpolar organic or inorganic reagents and/or analyte molecules in water in the presence of the organized medium, allowing the use of an aqueous medium to perform the procedure. The possibility of conducting reactions and forming fluorescent organic or metal chelates in micellar (or other organized) media that are not observed in a bulk homogeneous solvent system serves to expand the scope of possible chemistries for design/development of new, unique, and improved fluorescent assays. Examples of fluorescent methods for determination of both organic and inorganic analytes are provided, which serve to illustrate the advantages and benefits accrued from the use of the micelles, vesicles, liposomes, or CDs in such procedures, along with experimental considerations and cautions in utilizing organized media.

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Trends in Immunoassay Techniques

Gómez‐Hens

Aguilar-Caballos

2010

Encyclopedia of Analytical Chemistry

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This article attempts to provide an overview of different approaches proposed to improve the performance of immunoassay techniques, most of which are used in routine clinical analysis and are finding wide acceptance in other analytical areas, such as environmental and food analysis. The term immunoassay here encompasses all the methods that involve the formation of antigen‐antibody complex to attain the separation and/or detection of analytes, including conventional immunoassays, immunosensors, and immunoaffinity techniques. Advances in the production of antibodies, in the availability of new labels, and in the immobilization of immunoreagents, which are allowing the improvement of the selectivity, sensitivity and robustness of these assays, are described. The recent use of different nanomaterials as labels, nanoscaffolds, and separation media in immunoassay techniques is especially emphasized. Also, the development of new approaches to increase the usefulness of immunoassays for multianalyte detection is shown through the different microarray systems proposed. The efforts carried out to miniaturize immunoassays are described by discussing the usefulness of microfluidic systems. Finally, recent achievements in immunoextraction, alone or in combination with other separation techniques, such as liquid chromatography and capillary electrophoresis, are also included.

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Progress in Lanthanides as Luminescent Probes

Cited by 437 publications

References 145 publications

Increasing lanthanide luminescence by use of the RETEL effect

Increasing lanthanide luminescence by use of the RETEL effect

Fluorescence in Organized Assemblies

Trends in Immunoassay Techniques

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