Sensitive and fast detection of tetracycline using an aptasensor

Tetracycline (TET) is one of the most extensively used antibiotics in humans and animals. Fast and sensitive measurement of TET is of great interest. In this study, a triple-helix molecular switch (THMS) was developed for TET detection. The THMS consists of a target specific aptamer sequence and a signal transduction probe (STP). In the presence of a target, the aptamer binds to TET and the THMS complex is disassembled; so that the free STP is folded to a stem loop structure, and the fluorescence is quenched. In the absence of TET, the fluorescence is on. This sensor showed a high selectivity toward TET and a limit of detection (LOD) as low as 2.09 nM was obtained. Furthermore, our fabricated sensor was successfully used for TET detection and quantification in tap water and rat serum. It is expected that this sensor could be extended for the detection of other drugs.