期刊
ELECTROCHIMICA ACTA
卷 56, 期 25, 页码 9378-9385出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.electacta.2011.08.020
关键词
Potassium-doped multi-walled carbon nanotubes; Cholesterol oxidase; Cholesterol esterase; Total cholesterol; Direct electrochemistry
资金
- National Natural Science Funds for Distinguished Young Scholar [21025522]
- National Natural Science Funds for Creative Research Groups [20821063]
- 973 Program of China [2007CB936404]
- Nanjing University, China
We demonstrate herein a newly developed serum total cholesterol biosensor by using the direct electron transfer of cholesterol oxidase (ChOx), which is based on the immobilization of cholesterol oxidase and cholesterol esterase (ChEt) on potassium-doped multi-walled carbon nanotubes (KMWNTs) modified electrodes. The KMWNTs accelerate the electron transfer from electrode surface to the immobilized ChOx, achieving the direct electrochemistry of ChOx and maintaining its bioactivity. As a new platform in cholesterol analysis, the resulting electrode (ChOx/KMWNTs/GCE) exhibits a sensitive response to free cholesterol, with a linear range of 0.050-16.0 mu mol L-1 and a detection limit of 5.0 nmol L-1 (S/N =3). Coimmobilization of ChEt and ChOx (ChEt/ChOx/KMWNT5/GCE) allows the determination of both free cholesterol and esterified cholesterol. The resulting biosensor shows the same linear range of 0.050-16.0 mu mol L-1 for free cholesterol and cholesteryl oleate, with the detection limit of 10.0 and 12.0 nmol L-1 (S/N = 3), respectively. The concentrations of total (free and esterified) cholesterol in human serum samples, determined by using the techniques developed in the present study, are in good agreement with those determined by the well-established techniques using the spectrophotometry. (C) 2011 Elsevier Ltd. All rights reserved.
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