Layer-by-Layer Assembly of Hemoglobin and DNA Functionalized Carbon Nanotubes on Glassy Carbon Electrode: Direct Electrochemistry and Electrocatalysis

抄録

Layer-by-layer assembly of hemoglobin (Hb) with DNA functionalized singlewall carbon nanotubes (DNA-SWCNTs) was achieved on glassy carbon electrode surface based on the electrostatic attraction between positively charged Hb and negatively charged DNA-SWCNTs hybrids. Cyclic voltammogram of (Hb/DNA-SWCNTs)_n films modified electrodes showed a pair of well-defined and quasireversible redox peaks for Hb Fe(III)/Fe(II), indicating that direct electrochemistry of Hb was achieved. The dependence of the formal potential on solution pH indicated that one-proton transfer was coupled to each electron transfer in the direct electron transfer reaction. Additionally, Hb in the multilayer films retained its bioactivity and showed excellent electrocatalytic activity toward H₂O₂, suggesting that such multilayer films could be used as reagentless biosensors. The electrocatalytic current values were linear with increasing concentration of H₂O₂ in a wide range of 1–80 µM, with a low detection limit of 0.2 µM. The layer-by-layer assembly of enzymes with DNA-SWCNTs hybrids provided a general and useful way to construct sensitive biosensors without using mediators. On the other hand, this would be used as an easily prepared experimental model to fabricate functional nanostructured biointerfaces.