Label-free G-Quadruplex aptamer and Thioflavin-T based turn-off fluorescent detection of ethanolamine

A label free aptasensor based on G-quadruplex forming ethanolamine aptamers and Thioflavin T was developed for the selective and sensitive detection of ethanolamine. The detection system consists of DNA aptamers with four GGG repeats forming a G-quadruplex that Thioflavin T can easily bind to causing high fluorescence emission intensity because of its fluorescence molecular rotor nature. In the presence of ethanolamine, binding of aptamer to its target induces conformational changes causing the separation of Thioflavin T from the complex with a dramatic decrease in fluorescence intensity of reaction mixture. This fluorescence aptasensor has a convenient sensitivity and selectivity with a detection limit of 641 mu M to measure ethanolamine directly in contaminated water samples in a wide linear range. Furthermore this method avoids all complicated modification and labelling steps and thus offers a simple, fast, and cost efficient solution for ethanolamine detection.