Fluorescent reporter molecules

Fluorescent reporter molecules consisting of a single receptor, a single fluorophore, and a spacer electronically separating these two are popular probes since the... 

Fluorochromes are stains that interact directly with cellular components, or are used to form conjugates with antibodies or ligands, yielding fluorescent reporter molecules. O Table 13-1 lists a selection of fluoro- D Table 13-1 Fluorochromes for flow cytometry ... 

In conclusion, coupled with a simple fluorescent screening process, the sheer number of compounds generated by combinatorial chemistry may be as powerful a tool as rational design for finding small fluorescent reporter molecules. 

Most MIP optical sensors reported in the literature utilize fluorescence as the detectable signal [215, 216]. With fluorescent analytes, the fluorescence of the MIP will increase upon binding [217, 218]. With non-fluorescent analytes, a fluorescent reporter molecule can be applied. The reporter molecule competes with or is displaced by the analyte [219-221]. Alternatively, a fluorescent monomer can be incorporated in the polymer network [222]. Upon binding of the analyte, the fluorescence of the MIP is altered. 

A fiber-optic flow-injection analysis in which a fluorescent reporter molecule is utilized to monitor a competition reaction between a labelled and an unlabelled antigen molecule for an immobilized antibody has been reported [100]. It is based on the evanescent wave technique. 

In Chapter 10, Samnel Hemandez-Rivera and cowoikers show that Raman detection of trace amoimts of explosives and other hazardous materials on surfaces can be improved by ten to one thousand times with the addition of colloidal metallic nanoparticles to contaminated areas. Banahalli Ratna and colleagues demonstrate that orgarrized spatial distribution of fluorescent reporter molecules on a virus capsid eliminates the commonly encountered problem of fluorescence quenching. Using such viral nanoparticles, they show in Chapter 11 that enhanced fluorescence for the detection of protein toxins is possible. 

This study illustrates several potential advantages SERS possesses over other widely used biomedical spectroscopic tools such as fluorescence. For example, no fluorescent reporter molecule is needed for SERS, eliminating an assay step, thereby reducing assay time and cost. Additionally, the analyte-specific SERS spectrum may allow discrimination between specific binding to the assay substrate and nonspecific binding, which often plagues sandwich-type iimnunoassays. 

Dyes and Applications. The green fluorescence protein (GFP) is a strongly fluorescent reporter molecule that stems from the jellyfish Aquorea victoria [28]. It has a fluorescein-like characteristic, it requires no cofactors or substrates, and is species-independent. GFP engineering has produced different color mutants which have been used for gene expression, tracing of cell lineage, and as fusion tags to monitor protein localization [29],... 

A molecular probe with dual output signals offers two detection modes allowing use of the same probe in different environments. We have demonstrated how an AB2 self-immolative dendron with double quinone methide release mechanism can be applied to create a molecular probe with UV-Vis and fluorescence modes for the detection of a specific catalytic activity.15 The molecular probe is illustrated in Fig. 5.36. The central unit of the probe (the molecular adaptor) is linked to an enzymatic substrate that acts as a trigger and to two different reporter molecules. Cleavage of the enzymatic substrate triggers the release of the two reporters and a consequent activation of their signals. 

As far as we know, this is the first molecular probe that includes two different types of reporter units activated upon on a specific stimulus. The other option to achieve dual detection would be to use two separate probes. However, in this case there could be a problem of competitive catalysis (circumstances in which the Km of the two substrate is not identical). In our probe, 6-aminoquinoline and 4-nitrophenol, detected by fluorescence and absorbance spectroscopy, respectively, were used as reporter units. Due to the synthetic flexibility of our approach, other reporter molecules with different types of functional groups, like amine or hydroxyl, can be linked to our molecular probe. The two assays must be orthogonal to each other, in order to prevent disturbances in the detection measurement. Another advantage of the probe is the aqueous solubility... 

Anisotropy describes the rotational dynamics of reporter molecules or of any sensor segments to which the reporter is rigidly fixed. In the simplest case when both the rotation and the fluorescence decay can be represented by single-exponential functions, the range of variation of anisotropy (r) is determined by variation of the ratio of fluorescence lifetime (xF) and rotational correlation time ([Pg.9]

Proteases are one of the largest families of enzymes and are involved in a multitude of vital processes. Due to their biological relevance and diversity, multiple fluorescent reporters monitoring their activity have been designed and successfully applied in vitro and in vivo [112-114]. Standard small molecule FRET probes for proteases consist of an amino acid sequence flanked by a FRET pair, consisting of two fluorophores or one fluorophore and a quencher molecule. Upon cleavage of the peptide sequence, the emission of the donor fluorophore is dequenched and the intensity increases whereas the emission of the acceptor decreases and vanishes more or less completely in those cases where the acceptor is fluorescent (see Fig. 6.11). 

So, what s next Of course, research on all fronts will advance, with the approaches in Sect. 4 receiving perhaps the highest attention. The rapid development of nanoscopic and nanostructured materials has specially opened the path to sophisticated sensing ensembles Sousa and Vogtle would not even have dreamed about [228, 229]. However, for many applications, small molecules as reporters are indispensible, simply because of their size and the possibilities of interaction at the molecular level so that their future exploration is also essential. Finally, since technology will advance, new instrumental techniques and possibilities will appear and automatically fuel research on powerful fluorescent reporters. 

Przhonska OV, Webster S, Padilha LA et al (2010) Two-photon absorption in near-IR conjugated molecules design strategy and structure-property relations. In Demchenko AP (ed) Advanced fluorescence reporters in chemistry and biology. I. Springer Ser Fluoresc 8 105-147... 

Based on the specific requirements for the operation of fluorescence reporters, we have divided them into two broad categories [2]. One category comprises reporters that serve as labels and tags. Their only response is based on their presence in a particular medium or at a particular site, and the major parameters that have to be optimized are their brightness and photostability. Brightness and durability can be increased dramatically if, instead of single molecules, we use nanoscale structures containing hundreds or thousands of them, and if we incorporate... 

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