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 mu M, low detection limit of 0.2 mu M, high sensitivity of 744 mu A 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. (C) 2012 Elsevier B.V. All rights reserved.