A 3D hollow structure composed of 2D nanosheets arranged in an ordered orthogonal manner for chlorpyrifos detection

The development of quantitative and portable analytical platforms for ultrasensitive pesticide detection is pivotal for advancing food safety monitoring. While electrochemical biosensors utilizing two-dimensional (2D) nanomaterials show significant potential in this area, the tendency of these materials to aggregate poses a considerable limitation to their development. Herein, to address these challenges, a three-dimensional (3D) hollow CuO@CuFeO_x structure with orthogonally aligned wrinkled nanosheets (denoted as H-COOWN) was synthesized. This hierarchical architecture not only addressed the critical issue of 2D nanosheet stacking, but also provided large surface area and more active sites. Besides, charge and mass transfer rates were also enhanced. When functionalized as an acetylcholinesterase-based biosensor, the H-COOWN platform achieved exceptional performance for chlorpyrifos detection, with a broad linear range (3.6 ×10^-14 M to 3.6 ×10^-6 M) and a low detection limit (3.32 ×10^-15 M). This work establishes a universal design paradigm for mitigating aggregation in 2D nanomaterial systems while expanding their potential applications in electrochemical sensing.