A simple and programmed DNA tweezer probes for one-step and amplified detection of UO₂²

A simple DNA tweezer was proposed for one-step and amplified detection of UO₂²⁺ based on DNAzyme catalytic cleavage. The two arms of DNA tweezers are close in the original form. Thus, the fluorescent signal of fluorophore at the end of arm is dramatically quenched. However, the structure of DNA tweezers can be changed from "close" to "open" in the presence of UO₂²⁺, resulting the strong fluorescent signal. The linear range was obtained in the range of 0.1 nM to 60 nM and the limit of detection was 25 pM with the amplification of DNAzyme catalytic cleavage reaction. Importantly, the whole detection process is very simple and only one operation step is required. In addition, it shows great potential and promising prospects for uranyl detection in practical application.