Direct electron transfer and enzymatic activity of hemoglobin in a hexagonal mesoporous silica matrix

被引:256
作者
Dai, ZH [1 ]
Liu, SQ [1 ]
Ju, HX [1 ]
Chen, HY [1 ]
机构
[1] Nanjing Univ, Dept Chem, Inst Analyt Sci, State Key Lab Coordinat Chem, Nanjing 210093, Peoples R China
基金
中国国家自然科学基金; 高等学校博士学科点专项科研基金;
关键词
biosensors; hemoglobin; hexagonal mesoporous silica; glassy carbon electrode; direct electron transfer; hydrogen peroxide; nitrate;
D O I
10.1016/j.bios.2003.08.024
中图分类号
Q6 [生物物理学];
学科分类号
071011 ;
摘要
The direct electrochemistry of hemoglobin (Hb) immobilized on a hexagonal mesoporous silica (HMS)-modified glassy carbon electrode was described. The interaction between Hb and the HMS was investigated using UV-Vis spectroscopy, FT-IR, and electrochemical methods. The direct electron transfer of the immobilized Hb exhibited two couples of redox peaks with the formal potentials of -0.037 and -0,232 V in 0.1 M (pH 7.0) PBS, respectively, which corresponded to its two immobilized states. The electrode reactions showed a surface-controlled process with a single proton transfer at the scan rate range from 20 to 200 mV/s. The immobilized Hb retained its biological activity well and displayed an excellent response to the reduction of both hydrogen peroxide (H2O2) and nitrate (NO2-). Its apparent Michaelis-Menten constants for H2O2 and NO2- were 12.3 and 49.3 muM, respectively, showing a good affinity. Based on the immobilization of Hb on the HMS and its direct electrochemistry, two novel biosensors for H2O2 and NO2- were presented. Under optimal conditions, the sensors could be used for the determination of H2O2 ranging from 0.4 to 6.0 muM and NO2- ranging from 0.2 to 3.8 muM. The detection limits were 1.86 x 10(-9) M and 6.11 X 10(-7) M at 3sigma, respectively. HMS provided a good matrix for protein immobilization and biosensor preparation. (C) 2003 Elsevier B.V. All rights reserved.
引用
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页码:861 / 867
页数:7
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