Sensors fluorescence

Fig. 3a, b. Schematic representation of (a) conventional fluorescent sensor and (b) fluorescent sensor with signal amplification. Open rhombi indicate coordination sites and black rhombi indicate metal ions. The curved arrows represent quenching processes. In the case of a den-drimer, the absorbed photon excites a single fluorophore component, which is quenched by the metal ion regardless of its position... 

It has been demonstrated that dendrimers can be used also as fluorescent sensors for metal ions. Poly(propylene amine) dendrimers functionalized with dansyl units at the periphery like 34 can coordinate metal ions by the aliphatic amine units contained in the interior of the dendrimer [80]. The advantage of a dendrimer for this kind of application is related to the fact that a single analyte can interact with a great number of fluorescent units, which results in signal amplification. For example, when a Co ion enters dendrimer 34, the fluorescence of all the 32 dansyl units is quenched with a 32-fold increase in sensitivity with respect to a normal dansyl sensor. This concept is illustrated in Fig. 3. 

James TD (2007) Saccharide-Selective Boronic Acid Based Photoinduced Electron Transfer (PET) Fluorescent Sensors. 277 107-152... 

Demchenko AP (2005) The future of fluorescence sensor arrays. Trends Biotechnol 23 456 160... 

This is the first Cys fluorescent sensor derived from FONs, in which the fluorescence enhancing property is in conjunction with a remarkable red-shifted fluorescence emission. Despite the potential sources of error when considering complicated clinical samples, the authors believe that this probe can be applied to study the effects of Cys in a biological system. 

The quantum yields are 0.15-0.21 in ethanol and 0.01-0.02 in an aqueous medium, but in micelles, the quantum yields are five to tenfold increased. The aggregation of these dyes was studied in [53]. The amphiphilic squaraines 4 combine favorable photophysical properties and good solubility in aqueous media and in addition interact efficiently with micelles, and therefore have the potential to be used as NIR fluorescent sensors. However, our own investigations show that aniline-based squaraines lack chemical and photochemical stability when compared to oxo-squaraines with heterocyclic end-groups. 

Benzimidazolium is one of the typical scaffolds of the hemicyanine group, and cationic hemicyanine derivatives can be assumed as potential fluorescent sensors due to their electrostatic interactions. Based on this assumption, Chang and... 

Kundu K, Knight SF, Willett N, Lee S, Taylor WR, Murthy N (2009) Hydrocyanines a class of fluorescent sensors that can image reactive oxygen species in cell culture, tissue, and in vivo. Angew Chem Int Ed 48 299-303... 

Koskela SJM, Fyles TM, James TD (2005) A ditopic fluorescent sensor for potassium fluoride. Chem Commun 7 945-947... 

Farruggia G, Iotti S, Prodi L et al (2005) 8-hydroxyquinoline derivatives as fluorescent sensors for magnesium in living cells. J Am chem soc 128 344—350... 

Arimori S, Bell ML, Oh CS et al (2001) Molecular fluorescence sensors for saccharides. Chem Commun 18 1836—1837... 

Klymchenko AS, Demchenko AP (2002) Electrochromic modulation of excited-state intramolecular proton transfer the new principle in design of fluorescence sensors. J Am Chem Soc 124 12372-12379... 

Having thus illustrated the use of organic ligands as fluorescent sensors, we will now consider the applications of the photophysical properties of coordination compounds themselves. All the... 

Fluorophores are relative small molecules that, with some exceptions, are not naturally occurring and have to be synthesized chemically. There has been a large development in the synthesis of fluorescent molecules and nowadays there is a vast range of alternatives including dyes with improved photochemical properties, solubility or modified reactivity that allow for conjugation to other molecules of interest and the synthesis and application of fluorescent sensors [10, 13], Although a lot is known about the physics of fluorescence and a lot of information is available about the properties of dyes, their prediction from the chemical structures cannot be accurately done. For this reason, there has been a... 

Tung, C. H., Gerszten, R. E., Jaffer, F. A. and Weissleder, R. (2002). A novel near-infrared fluorescence sensor for detection of thrombin activation in blood. Chembiochem 3, 207-211. 

Sharma, V., Wang, Q. and Lawrence, D. S. (2008). Peptide-based fluorescent sensors of protein kinase activity Design and applications. Biochim Biophys. Acta. 1784, 94—99. 

Wolfbeis O.S., Offenbacher H., Kroneis H., Marsoner H. A fast responding fluorescence sensor for oxygen. Mikrochim. Acta 1984 I 153. 

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Prasanna de Silva A, Gunaratne H.Q.N., Gunnlaugsson T., Huxley A.J.M., McCoy C.P., Rademacher J.T., Rice T.E., Signaling Recognition Events with Fluorescent Sensors and Switches, Chem. Rev. 1997 97 1515 (review). 

Zhujun Z., Seitz W.R., A fluorescent sensor for aluminum(III), magnesium(II), zinc(II) and cadmium(II) based on electrostatically immobilized quinolin-8-ol sulfonate. Anal. 

Saari L.A., Seitz W.R., Immobilized morin as fluorescence sensor for determination of aluminum(III), Anal. Chem. 1983 55 667. 

Lubbers D.W., Opitz N., Optical fluorescence sensors for continuous measurement of chemical concentrations in biological systems, Sensors Actuat. 1983 3 641. 

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