Fluorescein 5 -carboxyfluorescein

Fluorescein absorbance is sensitive to pH. This property is utilized to measure cytosolic pH changes. Fluorescein derivatives that contain esters on the carboxyl groups have been constructed. These compounds partition through the cell membrane and, once inside the cell, the esters are cleaved by nonspecific esterases in the cytosol, leaving free carboxyl groups thus the probe cannot diffuse out of the cell (or at least does so slowly). Commonly used derivatives are 6-carboxyfluorescein (21-23) and the more recently developed probe 2, 7 -bis(2-carboxyethyl)-5(and-6)-carboxyfluorescein (13, 24,25). 

Among the commercially available fluorescein derivatives that have been widely used are fluorescein isothiocyanate (FITC) 49, carboxyfluorescein (FAM) succini-midyl ester 50, and fluorescein dichlorotriazine (DTAF) 51. FITCs are the most commonly used fluorescein derivatives. They have been used to react with sulfhy-dryl [127], targeting reduced cysteine chains and especially amino groups in peptides or proteins [128]. 

Figure 5 shows two typical core-shell structures (a) contains a metal core and a dye doped silica shell [30, 32, 33, 78-85] and (b) has a dye doped silica core and a metal shell [31, 34]. There is a spacer between the core and the shell to maintain the distance between the fluorophores and the metal to avoid fluorescence quenching [30, 32, 33, 78-80, 83]. Usually, the spacer is a silica layer in this type of nanostructures. Various Ag and Au nanomaterials in different shapes have been used for fluorescence enhancement. Occasionally, Pt and Au-Ag alloys are selected as the metal. A few fluorophores have been studied in these two core-shell structures including Cy3 [30], cascade yellow [78], carboxyfluorescein [78], Ru(bpy)32+ [31, 34], R6G [34], fluorescein isothiocyanate [79], Rhodamine 800 [32, 33], Alexa Fluor 647 [32], NIR 797 [82], dansylamide [84], oxazin 725 [85], and Eu3+ complexes [33, 83]. 

In a particle concentration fluoroimmunoassay system that is based on microtiter plates with 0.22-/ filters on the bottoms, microparticles are used with a flowthrough wash system. Either fluorescein-labeled antibodies or cells serve as labels.(41) Car-boxyfluorescein diacetate, which crosses the cell membrane, is hydrolyzed by cytoplasmic esterases, thereby trapping carboxyfluorescein within the cell. The method is also useful for screening and isotyping antibodies. 

Fig. 2 Determination of IgE using aptamer-based APCE. (A) Electropherograms obtained for 500 nM of A with 0 (left) and 500 nM (right) IgE. Migration buffer was 10 mM phosphate at pH 7.4, and 10 nM fluorescein was used as internal standard (IS). Injector-to-detector length was 20 cm. (B) Separation of same solutions in 10 mM phosphate at pH 8.2 and gravity-induced flow of 0.02 cm/s. (C) Solutions of 300 nM of A with no IgE (left), 300 nM IgE (middle), and 1 nM IgE (right) were separated with injector-to-detector length of 7 cm. After 48 s of separation, a vacuum was applied to the outlet to rapidly pull the complex to the detector. 4(5)-Carboxyfluorescein (5 nM) was used as internal standard. Fluorescent signal scale for the 1 nM IgE sample is expanded by 10-fold relative to the other electropherograms. (From Ref. 26.)...

Applications of fiber-optic pH sensors in environmental analysis, biomedical research, medical monitoring, and industrial process control have been reviewed by Lin [67]. A multitude of luminescent systems for pH monitoring are commercially available, mostly under special trademarks. Pyrene [68-70], coumarin, bromothymol blue [71] and fluorescein [72-74] derivatives are typical examples that have been used in research in the past two decades. Carboxyfluorescein derivatives have been directly applied to skin tissue samples for the lifetime imaging of pH gradients in the extracellular matrix of the epidermis [75]. Two-photon excitation microscopy became an estab-... 

Breeuwer, P., Drocourt, J. L, Bunschoten, N., Zwietering, M. H., Rombouts, F. M. and Abee, T. Characterization of uptake and hydrolysis of fluorescein diacetate and carboxyfluorescein diacetate by intracellular esterases in Saccharomyces cerevisiae, which result in accumulation of fluores-... 

Permeabilization with carboxyfluorescein-diacetate. 6-carboxy-fluorescein-diacetate (CFDA) is a nonfluorescent, nonpolar reagent which enters the cell freely, where it becomes entrapped following enzymatic conversion to the hydrophilic fluorophore 6-carboxyfluorescein (CF, mw 370). Thus, labeled cells can then be replated onto unlabeled test cells to measure dye transfer via gap junction. This method has been successfully used to measure gap junction communication in early embryo cells (Goodall and Johnson, 1982 Kidder et al., 1987), and also to label tumor cells in culture (Price et al., 1995). We tried to extrapolate it for detection of gap junction formation among cultured cells. 

Compound 128 has been synthesized by reaction of fluorescein methyl ester and 4-chloro-l-(4,4 -dimethoxytrityloxy)butane followed by detritylation and phosphitylation with bis-(N,N-diisopropylamino)methoxyphosphine. The phosphoramidite has been used for direct ligand incorporation at the 5 -end [319]. Synthesis of compound 129 proceeds from 5-carboxyfluorescein and isopropylidene glycerol (solketal). Incorporation at the 5 - or 3 -... 

Near-neutral pH fluorescein diacetate, carboxyfluorescein and Its esters, 5-sulfofluorescein diacetate, BCECF Acidic pH di- and trifluorofluoresceins (Oregon Green) and dichlorofluores-cein, 9-amino-6-chloro-2-methoxyacri-dine, 8-hydroxypyrene-l,3,6-trisulfonic acid (HPTS)... 

OtherNames Spiro[phthalan-l,9 -xanthene]-6-carboxylicacid,3, 6 -dihydroxy-3-oxo- Terephthalic acid, (3,6,9-tTihydroxyxanthen-9-yl)-, y-lactone 6-Carboxyfluorescein 6-FAM 6-carboxyfluores-cein Fluorescein, 6-carboxy-... 

Figure 21-12. Plot of In(kigt) vs. the driving force (Eo-o) for back electron transfer to the cation radical of the compounds. Eo-o is a linear function of—d G. The compounds are (a) eosin yellowish (EOY), (b) dibromo fluorescein (DBF), (c) fluorescein isothiocyanate (FITC), (d) fluorescein (FLU), and (f) 5(6)-carboxyfluorescein (56CF) (taken with permission from Ramakrishna, 2001).

TEOS nanoparticles doped with three types of dye were prepared for fluorescence-resonance energy transfer (FRET) by means of imposition [55]. The dyes fluorescein, 5-carboxyrhodamine 6G (R6G) and 6-carboxy-X-rhodamine (ROX) were used to prepare these TEOS nanoparticles because their spectral features effectively overlap. In the triple-dye-doped TEOS nanoparticles, fluorescein was used as a common donor for R6G and ROX, whereas R6G acted both as an acceptor for fluorescein isothiocyanate (FITG) and as a donor for ROX. To prepare the nanoparticles, the three types of amine-reactive dye molecule were first covalently linked to APS, 5-(and-6)-carboxyfluorescein succinimidyl ester, 5-carboxyrhodamine 6G succinimidyl ester and 6-carboxy-X-rhodamine succinimidyl ester. 

Rockey, J. H. Li, W. Eccleston, J. F. Binding of fluorescein and carboxyfluorescein by human serum proteins significance of kinetic and equilibrium... 

CA Index Name Spiro[isobenzofuran-l(3i7),9 -[9/7] xanthene]-6-carboxylic acid, 3, 6 -dihydroxy-3-oxo-Other Names Spiro[phthalan-l,9 -xanthene]-6-carboxylic acid, 3, 6 -dihydroxy-3-oxo Terephthalic acid, (3,6,9-trihydroxyxanthen-9-yl)-, y-lactone 6-Carboxyfluorescein 6-FAM Fluorescein, 6-carboxy-Merck Index Number Not listed Chemical/Dye Class Xanthene Molecular Formula C21H12O7 Molecular Weight 376.32 Physical Form Orange solid... 

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