Ultrasensitive electrochemical detection of UO22+ based on DNAzyme and isothermal enzyme-free amplification

A novel strategy for ultrasensitive detection of UO22+ was proposed by using a UO22+-specific DNAzyme and two free labeled DNA hairpins. The principle and detection processes of this electrochemical biosensor for amplification detection of UO22+ were described. The detection conditions of the biosensor, such as the concentration of hairpins, pH, and the incubation time of HCR, were optimized. Under optimal conditions, this biosensor demonstrated a high sensitivity of UO22+ detection with the dynamic concentration range spanning from 0.05 to 4 nM and a detection limit of 20 pM at the 3Sblank level, providing a promising strategy for on site and real-time monitoring of uranium.