Direct electrochemistry and electrocatalysis of hemoglobin immobilized on an interlaced Co(OH)2 nanosheet-based three-dimensional macroporous film

Hemoglobin (Hb) has been successfully immobilized on a glassy carbon (GC) electrode modified by an interlaced Co(OH)2 nanosheet-based three-dimensional (3D) macroporous film prepared by a cathodic electrodeposition method. The surface morphology of the Co(OH)2 film was examined by scanning electron microscopy. UV–vis spectra revealed that the Hb immobilized on the Co(OH)2 film retained its native structure. A fast direct electron transfer was achieved between Hb and the underlying electrode, with an average electron transfer rate of 7.8 s−1. The resulting biosensor exhibited good performance for the detection of H2O2, with a wide linear range from 0.4 to 200 μM, low detection limit of 0.2 μM, high sensitivity of 744 μA mM−1 cm−2, excellent stability and reproducibility. The cathodic electrodeposition method provides a simple and efficient way to prepare a 3D nanostructured film for immobilizing protein or enzyme, and the resulting film has potential applications in biosensors, catalytic bioreactors, and biomedical devices.