Direct Electron Transfer of Redox Proteins and Enzymes Promoted by Carbon Nanotube

Authors

Chen-xin CAI, Department of Chemistry, Nanjing Normal University, Nanjing 210097, ChinaFollow
Jing CHEN, Department of Chemistry, Nanjing Normal University, Nanjing 210097, China

Corresponding Author

Chen-xin CAI(cxcai@njnu.edu.cn)

Abstract

The redox proteins (enzymes), such as hemoglobin (Hb), horseradish peroxidase (HRP) and glucose oxidase (GOx) were immobilized on the surface of the carbon nanotube modified with glassy carbon (CNT/GC) electrode, respectively. The experimental results showed that the redox proteins (enzymes) underwent effective and stable direct electron transfer reaction at the surface of CNT/GC electrode with a pair of nearly symmetrical redox peaks in phosphate buffer solution. The formal redox potential, E^0' , is almost independent on the scan rates, the average value of E^0' for Hb, HRP and GOx is -0.343±0.001, -0.319±0.002 and -0.456±0.001 V (vs.SCE,pH 6.9), respectively. The dependence of E^0' on the pH of the buffer solution indicates that the direct electron transfer of Hb and HRP is a one-electron-transfer reaction process coupled with one-proton-transfer, while the GOx is a two-electron-transfer reaction process coupled with two-proton-transfer. The experimental results also demonstrated that the immobilized Hb and HRP retained their bioelectrocatalytic activity to the reduction of H₂O₂ , and immobilized GOx can catalyze the oxidation of glucose in the presence of ferrocene monocarboxylic acid. The method presented here can be easily extended to immobilize and obtain the direct electrochemistry of other redox enzymes or proteins. Highly ordered CdS nanowire arrays have been prepared by using dc electrodeposition in the porous anodic aluminum oxide template. Scanning electro microscopy (SEM) and transmission electron microscopy (TEM) reveal that the nanowires are uniform and highly ordered. The measurements of X-ray diffraction and high-resolved electron microscopy (HRTEM) show that the nanowires are hexagonal structure with the crystallographic c-axis preferentially oriented along the length of the pore. The UV-Vis absorption spectra of CdS nanowire arrays show that the absorption edges of the nanowire arrays shift towards short wavelength with the decrease of the nanowire size. The photoluminescence measurements show that the PL intensity increases after the AAO is filled with CdS nanowires, and a strong fluorescence peak appears. At the same time, we also find that the fluorescence characteristics in visible region are independent on the excitation wavelength.

Keywords

Carbon nanotube, Direct electrochemistry, Hemoglobin, Horseradish peroxidase, Glucose oxidase

DOI Link

https://doi.org/10.61558/2993-074X.1561

Publication Date

2004-05-28

Online Available Date

2004-05-28

Revised Date

2004-02-13

Received Date

2004-01-05

Recommended Citation

Chen-xin CAI, Jing CHEN. Direct Electron Transfer of Redox Proteins and Enzymes Promoted by Carbon Nanotube[J]. Journal of Electrochemistry, 2004 , 10(2): 159-167.
DOI: 10.61558/2993-074X.1561
Available at: https://jelectrochem.xmu.edu.cn/journal/vol10/iss2/7