Electrochemical Surface Structuring with Polyaniline Wrapped Hb for Hydrogen Peroxide Biosensing

Through the electrodeposition of aniline with hemoglobin (Hb) on zincoxide-gold colloidal sols (ZnO-AuNPs) modified indium oxide electrode, a hydrogen peroxide (H2O2) biosensor was constructed. Polyaniline (PAN I) form a nano-cage wrapped Hb, which provided a comfortable and stable site for the immobization of Hb. UV-vis spectrum was employed to characterize Hb retained original structure in the resulting Hb-PANI/ZnO-AuNPs membrane. Electrochemical investigation of the biosensor showed a pair of well-defined, quasi-reversible redox peaks with E-pa = -0.139 V and E-pc = -0.238 V (vs. SCE) in 0.1 M pH 7.0 phosphate buffer solution at the scan rate of 100 mV/s. The biosensor displayed a fast response time (< 3 s) and broad linear response to H2O2 in the range from 1.5 mu M to 1.7 mM with a detection limit of 0.8 mu M (S/N = 3).