Direct Electrochemistry and Electrocatalysis of the Hemoglobin Immobilized on Diazonium‐Functionalized Aligned Carbon Nanotubes Electrode |
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Authors: | Jing Yang Ying Xu Renyi Zhang Yanzhi Wang Pingang He Yuzhi Fang |
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Institution: | Department of Chemistry, East China Normal University, Shanghai 20062, P.?R. China |
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Abstract: | A simple and efficient electrochemical method is utilized to functionalize aligned carbon nanotubes (ACNTs) by the electrochemical reduction of 4‐carboxyphenyl diazonium salt. Thus hemoglobin (Hb) molecules were covalently immobilized on the diazonium‐ACNTs surface via carbodiimide chemistry. Direct electrochemistry and bioelectrocatalytic activity of the immobilized Hb were then investigated by cyclic voltammetry (CV) and amperometry techniques. It is showed that the Hb film on the diazonium‐ACNTs electrode had well‐defined redox peaks with a formal potential (E°) at ?312 mV (vs. Ag/AgCl), and the Hb‐ACNTs electrode displayed good electrocatalytic activity to H2O2 reduction. Owing to the high Hb covering on the ACNTs surface (Γ*=2.7×10?9 mol cm?2), the catalytic current were significantly improved when compared to the current measured at an Hb‐tangled carbon nanotubes electrode. The Hb‐ACNTs electrode exhibited high sensitivity, long‐term stability and wide concentration range from 40 μM to 3 mM for the amperometric detection of H2O2. The heterogeneous reaction rate constant (ks) was 0.95±0.05 s?1 and the apparent Michaelis–Menten constant (K was 0.15 mM. |
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Keywords: | Aligned carbon nanotubes Diazonium reaction Hemoglobin Electrocatalysis Biosensors Nanotubes |
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