Hb-PDDA films were constructed by encapsulating hemoglobin (Hb) in PDDA matrix and modified on the glassy carbon electrode (GCE), where PDDA is a polycation poly(diallyldimethylammonium chloride), realizing the direct electrochemistry between Hb and the electrode surface without any nanomaterial. UV-Vis absorption testified Hb could still keep its native structure in Hb-PDDA films. The influence of the ethanol proportion to the electrochemistry of Hb-PDDA/GCE was investigated in PBS-ethanol mixtures by cyclic voltammetry (CV). CV of Hb-PDDA/GCE showed a pair of reversible and stable peaks at 0.350 and 0.412 V (vs. SCE) in PBS-ethanol solution (V:V/1:1, pH 7.0) at the scan rate of 100 mV/s, with a electron transfer rate constant 1.03 s1. Hb-PDDA/GCE also achieved the electrocatalytic reduction to H2O2 at 0.42 V (vs. SCE), with a smaller apparent Michaelis-Menten constant 0.496 mM and a lower detection limit 0.96 μM. Therefore, this method of fabricating chemically modified electrode takes on a significant potential in preparation of the third-generation biosensors.
Specialized Research Fund for the Doctoral Program of Higher Education （200801451023）
College of Sciences, Northeastern University, Shenyang 110004,College of Sciences, Northeastern University, Shenyang 110004