Detection of uranyl ions by single-hairpin based self-hybridization chain reaction

Uranium is a toxic radionuclide, and its most stable and common ionic form is water-soluble uranyl ions (UO₂²⁺), which migrates into the environment easily and causes adverse effects on environment and human health. Herein, by cleverly designing the stem of DNA hairpin with palindromic sequence, a self-hybridization chain reaction (SHCR) system was developed for sensitive UO₂²⁺ detection. This detection system showed a good linear correlation between the ratio of fluorescence intensities and UO₂²⁺ concentration within the range of 0.05 nM-20 nM, and the detection limit was calculated to be 0.017 nM. Unlike the traditional HCR system which involves two hairpins, this proposed SHCR system only needs one DNA hairpin, which reduces the complexity of sequence design and experimental operation. And it can be used for the detection of other non-nucleic acid targets by simply changing the target molecule recognition module.