Direct Electrochemistry and Electrocatalysis of Hemoglobin/ZnO-Chitosan/nano-Au Modified Glassy Carbon Electrode

The highly efficient H2O2 biosensor was fabricated on the basis of the complex films of hemoglobin (Hb), nano ZnO, chitosan (CHIT) dispersed solution and nano Au immobilized on glassy carbon electrode (GCE). Biocompatible ZnO-CHIT composition provided a suitable microenvironment to keep Hb bioactivity (Michaelis-Menten constant of 0.075 mmol L-1). The presence of nano Au in matrix could effectively enhance electron transfer between Hb and electrode. The electrochemical behaviors and effects of solution pH values were carefully examined in this paper. The (ZnO-CHIT)-Au-Hb/GCE demonstrated excellently electrocatalytical ability for H2O2. This biosensor had a fast response to H2O2 less than 4s and excellent linear relationships were obtained in the concentration range from 1.94 x 10(-7) to 1.73 x 10(-3) mol L-1 with the detection limit of 9.7 x 10(-8) mol L-1 (S/N=3) under the optimum conditions. Moreover, the stability and reproducibility of this biosensor were evaluated with satisfactory results.