Electrochemical Biosensor Based on Carbon Ionic Liquid Electrode Modified with Nafion/Hemoglobin/DNA Composite Film |
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Authors: | Wei Sun Yan Wang Xiaoqing Li Jie Wu Tianrong Zhan Kui Jiao |
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Affiliation: | Key Laboratory of Eco‐Chemical Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, P.?R. China |
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Abstract: | A new electrochemical biosensor was constructed by immobilization of hemoglobin (Hb) on a DNA modified carbon ionic liquid electrode (CILE), which was prepared by using 1‐ethyl‐3‐methylimidazolium tetrafluoroborate (EMIMBF4) as the modifier. UV‐vis absorption spectroscopic result indicated that Hb remained its native conformation in the composite film. The fabricated Nafion/Hb/DNA/CILE was characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). A pair of well‐defined redox peaks was obtained on the modified electrode, indicated that the Nafion and DNA composite film provided an excellent biocompatible microenvironment for keeping the native structure of Hb and promoting the direct electron transfer rate of Hb with the basal electrode. The electrochemical parameters of Hb in the composite film were further calculated with the results of the charge transfer coefficient (α) and the apparent heterogeneous electron transfer rate constant (ks) as 0.41 and 0.31 s?1. The proposed electrochemical biosensor showed good electrocatalytic response to the reduction of trichloroacetic acid (TCA), H2O2, NO and the apparent Michaelis–Menten constant (KMapp) for the electrocatalytic reaction was calculated, respectively. |
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Keywords: | Ionic liquids 1‐Ethyl‐3‐methylimidazolium tetrafluoroborate Hemoglobin Direct electron transfer DNA |
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