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

摘要

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 H_2O_2 without any electron mediator. Under optimum conditions, the biosensor responded linearly to H_2O_2 in the concentration range of 1 × 10~(-6) to 2.5 × 10~(-2) M with detection limit of 1 × 10~(-7) M at 3σ. Moreover, the studied biosensor exhibited high sensibility, good reproducibility, and long-term stability.