Fluorescence sensing

In addition to the use of fluorescence in biochemistry and biophysics, there is a growing interest in its use for analytical and clinical chemistry. The use of fluorescence in clinical diagnostics is part of the continual shift away from the use of radioactive tracers. The use of optical methods eliminates the dangers of handling radioactive materials and the cost of their (roper disposal. 

Fluorescence is used for a wide variety of biomedical purposes. Fluorescence imaging of gels is used to detect DNA fragments following electrophoretic separation. The newer DNA stains provide hi detection sensitivity and can mostly replace the use of and autoradiography. The 

The essence of any experiment is the existence of an observable quantity and the correlation of the value of this observable with a phenomenon of interest. The time span between the absorption of light and its subsequent reemis-sion allows time for several processes, each of which results in changes of fluorescence spectral obsovables. These processes include collisions with quenchers, rota- 

finally, an impOTtant feature of flucnescence is that there is a rather direct connection between the spectral observables and molecular features of toe sample. It is easy to visualize how the spectral properties are affected by toe local environment, accessibility to quenchers, or the Nes-ence of nearby acceptors. It is this connection between what the molecules are doing and how this affects the emitted light which allows toe design of experiments toat answer our scientific questions. 

Herschel,SirJ.F.W., l84S,Onacaseofsupeificialcolourpcesrated by a homogeneous liquid IntMnaUy colourless, Pfdl. Trans. R. Soc. LTndoR 135U43-14S. 

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Fabbrizzi L (2000) (ed) Special issue of Coord Chem Rev on Fluorescence sensing, vol 205... 

Several parameters of fluorescence emission can be used as outputs in fluorescence sensing and imaging. Fluorescence intensity F can be measured at given... 

There are many possibilities to use these complex formations in fluorescence sensing. If the excimer is not formed, we observe emission of the monomer only, and upon its formation there appears characteristic emission of the excimer. We just need to make a sensor, in which its free and target-bound forms differ in the ability of reporter dye to form excimers and the fluorescence spectra will report on the sensing event. Since we will observe transition between two spectroscopic forms, the analyte binding will result in increase in intensity of one of the forms and decrease of the other form with the observation of isoemissive point [22]. 

Demchenko AP (2009) Introduction to fluorescence sensing. Springer, Amsterdam... 

Altschuh D, Oncul S, Demchenko AP (2006) Fluorescence sensing of intermolecular interactions and development of direct molecular biosensors. J Mol Recognit 19 459 477... 

Demchenko AP (2010) The concept of lambda-ratiometry in fluorescence sensing and imaging. J Fluoresc DOI 10.1007/sl0895-010-0644-y... 

Krioukov E., Greve J., Otto C., Performance of integrated optical microcavities for refractive index and fluorescence sensing, Sens. andActuat. B 2003 90 58-67. 

Xu Z, Singh NJ, Lim J et al (2009) Unique sandwich stacking of pyrene-adenine-pyrene for selective and ratiometric fluorescent sensing of ATP at physiological pH. J Am Chem Soc 131 15528-15533... 

Liu S, Pestano JPC, Wolf C (2008) Enantioselective fluorescence sensing of chiral alpha-amino alcohols. J Org Chem 73 4267-4270... 

McNamara KP, Nguyen T, Dumitrascu G, Ji J, Rosenzweig N, Rosenzweig Z (2001) Synthesis, characterization, and application of fluorescence sensing lipobeads for intracellular pH measurements. Anal Chem 73 3240-3246... 

Ben Othman A, Lee JW, Abidi R (2007) A novel pyrenyl-appended tricalix[4]arene for fluorescence-sensing of Al(in). Tetrahedron 63 10793-10800... 

Pinto MR, Schanze KS (2004) Amplified fluorescence sensing of protease activity with conjugated polyelectrolytes. Proc Natl Acad Sci 101 7505-7519... 

In cases where fluorescence sensing is accompanied by binding of the analyte (classes 2 and 3), the dissociation constant of the complex should match the ex-... 

A Novel Fluorescent Sensing Technique for Dipicolinic acid... 

In addition to these research applications of fluorescence, there is a continuing use of fluorescence detection to replace analytical methods based on radioactivity, as can be judged from the recent books and conferences on fluorescence sensing methods. (7 n) These emerging applications of fluorescence can be seen by the growth and introduction of improved methods for immunoassays, enzyme-linked immunoassays... 

The various possible schemes for fluorescence sensing are summarized in Figure 1.1. At present, most fluorescence assays are based on the standard intensity-based methods, in which the intensity of the probe molecule changes in response to the analyte of interest. However, there has been the realization that lifetime-based methods possess intrinsic advantages for chemical sensing. (A more detailed description of... 

Figure 1.1. Schemes for fluorescence sensing intensity, intensity ratio, time-domain, and phase-modulation, from left to right.

J. R. Lakowicz and R. B. Thompson, Advances in Fluorescence Sensing Technology, SPIE 1885, Billingham Washington (1993). 

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