Sensors quencher molecules

When compared to fluorescent proteins, fluorophores and quenchers of fluorescence (short quenchers) are small molecules with sizes varying from 1 to 10 A. They are the main building blocks for constructing small molecule FRET probes. As molecular entities, they might influence the performance of the probe to a great extent. Their fluorescent properties will determine the sensitivity and dynamic range of the sensor. The success of the probe for a specific application will depend on the selection of the right fluorophores... 

Several papers reported on the spatial determination of photoactive molecule in organized assemblies (76-79), and Pallavicini and coworkers reviewed on the use of luminescence as probe in self-assembly of multicomponent fluorescent sensors (80). Also, luminescence quenching studies on [Rufbpyls] in sodiiun dodecyl sulfate (SDS) micelles and hemimicelles by using a variety of quenchers were reported by Tiuro and coworkers (81) and then reviewed by De Schryver and coworkers (82). 

Luminescence quenching sensors can be explained by the following processes, where M represents the luminescing molecule and Q is a quencher ... 

Binding of molecules of TNT or any one of a suite of related nitroaromatic compounds commonly associated with the presence of TNT (for example, 2,4-dinitrotoluene), or photochemical or microbial degradation products of TNT (1,3-dinitrobenzene or amino-dinitrotoluenes) results in a dramatic reduction in the emission intensity of films of AFP. The reduction in emission intensity is proportional to the mass of quencher adsorbed by the films and is measured by the sensor system. A schematic of an early Fido prototype is shown in Figure 4. 

Many fluorescence sensors are based, not on direct fluorescence, but on the quenching of fluorescence. Molecular oxygen, for example, is one of the best col-lisional quenchers. Oxygen can quench the fluorescence from polycyclic aromatic hydrocarbons complexes of ruthenium, osmium, iridium, and platinum and a number of surface-adsorbed heterocyclic molecules. An oxygen sensor can be made by immobilizing the fluorophore in a thin layer of silicone on the end of a fiber-optic bundle. Sensors for SO-, haliilcs, H-O-, and several other molecules have been ba.sed on fluorescence quenching. 

A wide variety of molecules can act as quenchers (Chter 8), and they permit devdopment of sensors based on collisional quenching. Boizo[h]fluotoanthene was found to be highly sensitive to sulfur dioxide. Oxygen interfered with the measurements but was 26-fold less efficient as a quencher than SOz- Halogenated anesthetics ate known to quench protein fluraescence and can be detected by collisional quenching of anthracoie and petylene. Carbazole is quenched by a wide variety of chlorinated hydrocarbons. NO. which serves as a signal for blood vessel dilation, is also a collisional quencher. ... 

Wang et al. [50] have developed a method that could be generally applicable to the preparation of fluorescent sensors for nonfluorescent molecules by using an external fluorescence quencher in studying the binding of the imprinted fluorescent polymer. L-Tryptophan (Fig. 9, 3 was chosen as the template molecule and the... 

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