Cu _x O@DNA sphere-based electrochemical bioassay for sensitive detection of Pb²

The paper describes a one-step synthetic method to chemically reduce cupric sulfate by ascorbic acid in the presence of DNA strands to directly produce Cu _x O@DNA spheres. The DNA strands act as template to assist the preparation of Cu _x O, and also are capable of specifically binding  Pb(II) ions. The Cu _x O@DNA spheres possess high specific surface area and strong bioaffinity. They can be directly employed as platform for detecting Pb²⁺ sensitively. Electrochemical impedance spectroscopy data showed that the assay exhibits high sensitivity and a wide linear analytical range that extends from 0.1 to 100 nM, and the detection limit is 6.8 pM at a signal-to-noise ratio of 3. The assay is selective, acceptably reproducible, stable, and well feasible for the detection of Pb²⁺ in blood serum. Graphical abstract Schematic presentation of the preparation of DNA-templated Cu _x O spheres (Cu _x O@DNA) for use in electrochemical detection of Pb²⁺. The assay exhibits detection limit of 6.8 pM, high selectivity, acceptable reproducibility, stability, and good applicability for Pb²⁺ detection.