Abstract Cholesterol forms the basic structural components in the biological membrane and is present in several nerve tissues, brain and also serves as a source for the preparation of fatty acids. The determination of cholesterol level is significant in clinical diagnosis for heart problems, thrombosis etc. In this work, we report an electrochemical cholesterol biosensor based on cholesterol oxidase (ChOx) enzyme immobilized on gold nanoparticles – functionalized – multiwalled carbon nanotube (MWCNT) – polypyrrole (PPy) nanocomposite modified electrode. The sensor was fabricated by a two-step approach wherein the Au NPs- f -MWCNT was prepared by wet chemical method followed by electropolymerization of pyrrole. PPy act as a support matrix to hold ChOx and the presence of Au- f -MWCNT increases the electrical conductivity. Cyclic voltammetry (CV) exhibits a decrease in current with increasing cholesterol concentration which arises due to the competing action of Triton X100 surfactant employed for the preparation of cholesterol solution. The AuNPs- f -MWCNT-PPy-ChOx/GCE showed a linear response from 2 × 10 −3 to 8 × 10 −3 M in amperometry with a sensitivity and detection limit of 10.12 µA mM −1 cm −2 and 0.1 × 10 −3 M respectively. Further, the detection of cholesterol using impedance spectroscopy was also demonstrated. The reproducibility, stability and the validity of the sensor in biological samples were also examined.

中文翻译：

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用聚吡咯网络覆盖的金纳米粒子修饰的 f-MWCNT 开发胆固醇生物传感器

摘要 胆固醇是生物膜的基本结构成分，存在于多种神经组织、大脑中，也是制备脂肪酸的来源。胆固醇水平的测定对于心脏问题、血栓形成等的临床诊断具有重要意义。 在这项工作中，我们报告了一种基于固定在金纳米颗粒上的胆固醇氧化酶 (ChOx) 酶的电化学胆固醇生物传感器 - 功能化 - 多壁碳纳米管 (MWCNT) - 聚吡咯(PPy) 纳米复合改性电极。该传感器是通过两步法制造的，其中 Au NPs-f-MWCNT 是通过湿化学方法制备的，然后是吡咯的电聚合。PPy 作为支撑基质来保持 ChOx，Au-f-MWCNT 的存在增加了电导率。循环伏安法 (CV) 显示电流随着胆固醇浓度的增加而降低，这是由于用于制备胆固醇溶液的 Triton X100 表面活性剂的竞争作用而产生的。AuNPs- f -MWCNT-PPy-ChOx/GCE 在电流分析法中显示出从 2 × 10 -3 到 8 × 10 -3 M 的线性响应，灵敏度和检测限为 10.12 µA mM -1 cm -2 和 0.1 × 10 -3 M 分别。此外，还证明了使用阻抗谱检测胆固醇。还检查了传感器在生物样品中的重现性、稳定性和有效性。AuNPs- f -MWCNT-PPy-ChOx/GCE 在电流分析法中显示出从 2 × 10 -3 到 8 × 10 -3 M 的线性响应，灵敏度和检测限为 10.12 µA mM -1 cm -2 和 0.1 × 10 -3 M 分别。此外，还证明了使用阻抗谱检测胆固醇。还检查了传感器在生物样品中的重现性、稳定性和有效性。AuNPs- f -MWCNT-PPy-ChOx/GCE 在电流分析法中显示出从 2 × 10 -3 到 8 × 10 -3 M 的线性响应，灵敏度和检测限为 10.12 µA mM -1 cm -2 和 0.1 × 10 -3 M 分别。此外，还证明了使用阻抗谱检测胆固醇。还检查了传感器在生物样品中的重现性、稳定性和有效性。