Metal-organic framework-assisted Co3O4/CuO@CoMnP with core-shell nanostructured architecture on Cu fibers for fabrication of flexible wire-typed enzyme-free micro-sensors

Flexible fiber-based sensors have recently received increasing interest for real-time monitoring personal health, owing to their small size, high flexibility, lightweight, and application potentials in next-generation wearable electronics. Herein, we report a flexible wire-typed micro-sensor based on [email protected]3O4/CuO core–shell nanohybrid array on 1D Cu wire substrate for sensitive detection of glucose. The synthesis process involves in-situ growth of ZIF-67 rhombic dodecahedron on the surface of CuO nanotubes, followed by thermal annealing and electrodeposition of CoMnP nanoparticles to form core–shell nanostructured architectures. Benefiting from desirable hybrid nanostructures, the as-made binder-free fiber microelectrode exposes more electroactive sites for transport of ions and electrons during the catalytic process and provides strong adhesion between electroactive species and metal fiber substrate. As a glucose sensor, the [email protected]3O4/CuO fiber microelectrode displays favorable analytical properties, including two linear dynamic ranges of 0.001 mM – 0.55 mM and 0.55 mM – 3.03 mM with the sensitivities of 2445 μA mM−1cm−2 and 1774 μA mM−1cm−2, respectively, fast response time (1.62 s), excellent selectivity toward glucose at the presence interfering substances, and a low detection limit of 11.42 μM (S/N = 3). Moreover, the proposed wire-typed micro-sensor was successfully applied for measurement of glucose in human blood serum and saliva samples. Taking advantage of the versatility of 1D metal fiber current collector, MOF-assisted strategy and transition metal phosphides, the presented protocol here can be extended to the construction of other wearable and implantable sensing micro-devices.