A fluorescent sensor for L-tryptophan

Wang and co-workers [53] have succeeded in constructing a novel sensor based on the displacement of a small, structurally unrelated quencher from a MIP comprising a fluorescent functional monomer (Fig. 20.20). The principle of detection relies upon the enhanced fluorescence observed upon displacement of the quencher, p-nitrobenzaldehyde, from the L-tryptophan (r-Trp) binding sites within the polymer. 

At low concentrations ( 10 mM), tryptamine caused a small increase in the fluorescence intensity, presumably due to its ability to displace p-nitrobenzaldehyde from the binding sites by virtue of its resemblance to the template, but it was found that 10 mM tryptamine itself was able to quench the fluorescence of the MIP, albeit less than 1/lOth as effectively as / -nitrobenzaldehyde. In spite of shortcomings, such as the long incubation period, the biphasic nature of the system, the need for a specially designed functional monomer and its rather high detection limit (ca. 0.1 

Toward optical sensors for biologically active molecules 

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Liao, Y. Wang, W. Wang, B. Building Fluorescent Sensors by Template Polymerization The Preperation of a Fluorescent Sensor for L-Tryptophan. Bioorg. Chem. 1999, 27, 463 76. 

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