摘要: 本文介绍了一种通过钾掺杂碳纳米管修饰电极来单独固定胆固醇氧化酶或同时固定胆固醇氧化酶和胆固醇酯酶的新型胆固醇生物传感器。钾掺杂碳纳米管可以加快电子转移速率，继而引起胆固醇氧化酶和胆固醇酯酶的直接电化学作用的同时还保持其生物活性。作为胆固醇分析的一个新平台，对胆固醇和胆固醇油酸酯展现出高灵敏度。单独固定胆固醇的钾掺杂碳纳米管修饰电极的线性范围为 0。05 - 16 μM，检测限为0。005 μM（S/N = 3），同时固定胆固醇酶和胆固醇酯酶的钾掺杂碳纳米管修饰电极的线性范围为0。05 - 16 μM，检出限分别为0。010 μM（S/N = 3）和0。012 μM （S/N = 3）。此生物传感器针对胆固醇受到的常见的干扰，比如葡萄糖、抗坏血酸、尿酸、乳酸和谷氨酸的干扰等，表现出很高的灵敏度和选择性。实验结果表明，胆固醇氧化酶/钾掺杂碳纳米管修饰的玻碳电极和胆固醇酯酶/胆固醇氧化酶/钾掺杂碳纳米管修饰的玻碳电极在胆固醇和胆固醇酯检测中呈现稳定的高灵敏度，充分展现了胆固醇生物传感器应用前景。93805

毕业论文关键词: 钾掺杂多壁碳纳米管，胆固醇氧化酶，胆固醇酯酶，总胆固醇，直接电化学

ABSTRACT: We demonstrate herein a newly developed serum total cholesterol biosensor by using 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 (KMWCNTs) modified electrode。 The KMWCNTs membrane showed the excellent electrocatalytic activity toward the reduction of O2, H2O2, and the immobilized ChOx。 The K-doping accelerated the electron transfer from electrode surface to the immobilized ChOx, leading to the direct electrochemistry of ChOx。 Immobilization of ChOx on KMWCNTs modified electrode, the resulting electrode (ChOx/KMWCNTs/GCE) exhibits a sensitive response to free cholesterol, with a linear range of 0。05–16 μM and a detection limit of 0。005 μM (S/N=3)。 Coimmobilization of ChEt and ChOx allows the determination of both esterified cholesterol and free cholesterol。 The resulting biosensor showed the same linear range of 0。05–16 μM for cholesterol and cholestery loleate, with a detection limit of 0。010 μM（S/N=3）and 0。012 μM (S/N=3), respectively。 Apparent Michaelis constants of the ChOx/KMWCNTs/GCE and the ChEt/ChOx/KMWCNTs/GCE suggest that the response were controlled by penetration of the reaction substrates into the films of the enzyme(s), indicating that good application potential in biological electrochemistry。 源C于H优J尔W论R文M网WwW.youeRw.com 原文+QQ752-018766

Key words: potassium-doped multi-walled carbon nanotubes (KMWCNTs), cholesterol oxidase, cholesterol esterase, total cholesterol, direct electrochemistry

目  录

1  前言 4

2  实验部分 6

2。1  药品 6

2。2  仪器 6

2。3  制备胆固醇和胆固醇油酸酯溶液 6

2。4  合成钾掺杂多壁碳纳米管 7

2。5  制备酶修饰电极 7

3  结果与讨论 8

3。1  钾掺杂多壁碳纳米管的表征 8

3。2  KMWCNTs修饰电极的电化学交流阻抗表征和循环伏安图 11

3。3  基于胆固醇氧化酶的直接电化学法在KMWCNTs修饰电极上实现ChOx的单独固定以及 ChOx和ChEt的共同固定