A simple, sensitive and non-enzymatic signal amplification strategy driven by seesaw gate

Herein, a simple enzyme-free method based on the seesaw-gate-driven isothermal signal amplification strategy was developed for nucleic acid detection. In this method, a partially complementary double-stranded beacon was designed, after the addition of ssDNA or RNA of target sequence, the fluorescence signal was restored through a toehold-mediated strand displacement process, followed by a seesaw-like reaction with the aid of an auxiliary strand with the same length of the toehold domain. Liberation of the target would initiate the next round of seesaw reaction to achieve recycling amplification of the fluorescence signal. The method has the advantages of simple sequence design and free of any enzyme, which can realize rapid detection of the target at 25 °C with a detection limit of 9.8 pM for DNA and 83 pM for RNA. The potential applicability of the proposed method was also demonstrated, indicating that it can provide a fundamental strategy for the development of nucleic acid sensors.