Peptide-Mediated Nanopore Detection of Uranyl Ions in Aqueous Media

Uranium is one of the most common radioactive contaminants in the environment. As a major nuclear material in production, environmental samples (like soil and groundwater) can provide signatures on uranium production activity inside the facility. Thus, developing a new and portable analytical technology for uranium in aqueous media is significant not only for environmental monitoring, but also for nonproliferation. In this work, a label-free method for the detection of uranyl (UO<sub>2</sub><sup>2+</sup>) ions is developed by monitoring the translocation of a peptide probe in a nanopore. Based on the difference in the number of peptide events in the absence and presence of uranyl ions, nanomolar concentration of UO<sub>2</sub><sup>2+</sup> ions could be detected in minutes. The method is highly selective; micromolar concentrations of Cd<sup>2+</sup>, Cu<sup>2+</sup>, Zn<sup>2+</sup>, Ni<sup>2+</sup>, Pb<sup>2+</sup>, Hg<sup>2+</sup>, Th<sup>4+</sup>, Mg<sup>2+</sup>, and Ca<sup>2+</sup> would not interfere with the detection of UO<sub>2</sub><sup>2+</sup> ions. In addition, simulated water samples were successfully analyzed.