Direct electron transfer and electrocatalysis of hemoglobin adsorbed on mesoporous carbon through layer-by-layer assembly

Using chitosan as an effective linker between CMK-3 and glassy carbon electrode surface, {Hb/CMK-3}(n) multilayer film-modified electrodes were constructed through layer-by-layer assembly. The morphology of thus-formed f Hb/CMK-3 I,, film was characterized by scanning electron micrographs, and the interaction of hemoglobin (Hb) with CMK-3 was studied by UV-vis spectroscopy and electrochemical methods. Under optimal conditions, {Hb/CMK-3}(6) film showed a couple of stable and well-defined redox peaks at about -377 and -296 mV in pH 7.0 buffers. Furthermore, the {Hb/CMK-3}(6) film displayed excellent electrocatalysis to the reduction of both H2O2 and 0,. Based on thus-formed film and its direct electron transfer behavior, a novel biosensor was presented for the determination of H2O2 ranging from 1.2 to 57 mu M with the detection limit of 0.6 mu M at S/N = 3. CMK-3 provided a desirable matrix for protein immobilization and biosensor preparation. (c) 2006 Elsevier B.V. All rights reserved.