A hydrogen peroxide biosensor based on direct electrochemistry of hemoglobin in Hb-Ag sol films

Hemoglobin (Hb) was used as a template to fabricate hemoglobin-silver (Hb-Ag) sol in which the hemoglobin showed direct electrochemistry on a glass carbon (GC) electrode. Ultraviolet-visible (UV-vis) spectra and reflectance absorption infrared (RAIR) spectra suggested that hemoglobin in Hb-Ag sol retained its native secondary structure. Scanning electron microscopy (SEM) demonstrated that the morphology of the Hb film was much different from the Hb-Ag sol film. The Hb-Ag film proved to exhibit a good electrocatalytic activity for the reduction of hydrogen peroxide. Based on this, a novel amperometric hydrogen peroxide biosensor was developed, which showed a sensitive response to the reduction of H2O2 without any electron mediator. Under optimum conditions, the biosensor responded linearly to H2O2 in the concentration range of 1 x 10(-6) to 2.5 x 10(-2) M with detection limit of 1 x 10(-7) M at 3 sigma. Moreover, the studied biosensor exhibited high sensibility, good reproducibility, and long-term stability. (c) 2007 Published by Elsevier B.V.