Modular fluorescent sensors

Phillips MD, James TD. Boronic acid based modular fluorescent sensors for glucose. Journal of Fluorescence 2004, 14, 549-559. 

A Modular Strategy for Development of RNA-Based Fluorescent Sensors... 

We report the first examples of modular aptametric sensors which transduce recognition events into fluorescence changes through allosteric regulation of noncovalent interactions with a fluorophore (Stojanovic and Kolpashchikov,... 

Figure 12.6 Modular boronic acid ohotoinduced electron transfer (PET) fluorescence sensors.

It could be thought that altering the appended fluorophore on the modular diboronic acid systems would simply lead to fluorescent sensors with different emission and excitation wavelengths. As can be readily observed from the bar graph in Figure 40 this was not the case. 

Liu X, Yang X, Peng H, Zhu C, Cheng Y (2011) A fluorescent sensor for Hg and Ag functions as a modular switch based on click-generated triazole moiety. Tetrahedron Lett 52 2295-2298... 

Scrafton DK, Taylor JE, Mahon ME, Eossey JS, James TD (2008) Click-fluors modular fluorescent saccharide sensors based on a 1,2,3-triazole ring. J Org Chem 73 2871-2874... 

The modular structure of peptides and the well-established methods for their assembly enable the rapid synthesis of many structurally diverse catalyst candidates. For rapid screening of these Miller et al. developed the indicator 28 which becomes fluorescent on protonation (Scheme 12.14). In other words, catalyst candidates are usually incubated with acetic anhydride, the proton sensor 28 [32], and the two individual substrate enantiomers in separate microtiter plates. A related assay based on pH color indicators was developed by Davis et al. [34b],... 

The sensor developed by Gawley and co-workers is based on de Silva s modular approach comprises an azacrown ether linked to a fluorophore by a short link. The molecule combines the aza[18]crown-6 recognition element with a fluorescent coumaryl group attached by a methylene spacer. In tests it was shown to bind to saxitoxin with a binding constant on the order of 105 M 1, even in a phosphate buffer at physiological pH and concentrations of sodium and potassium, and could detect levels of the toxin down to 1(T7 M. Subsequent modification of the sensor allowed it to be linked to the surface of a quartz slide to allow the fluorescent response to concentrations of saxitoxin between 10-4 and 10-6 M to be detected via a fibre optic system. This level of sensitivity is comparable to the current mouse bioassay that requires the inoculation of a large number of animals to determine the concentration of saxitoxin present in the test sample [25],... 

Importantly, the goodness-of-fit parameters are satisfactory and the coefficient of the term involving (M +tolal) is near unity in all cases. Also, it must be noted that the stability constants for the alkali cation-benzocrown ether interaction available in the literature [30,48] agree closely with the values extracted from Fig. 5 for the alkali cation (14) association. All of this very gratifyingly support the expectations of the fluorescent PET sensor design logic in terms of a supermolecule with modular behaviour [43],... 

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