组成图示
点击图片查看大图 · 依据论文自动绘制
传感器类型
电化学生物传感器
检测对象
葡萄糖（glucose, β-D-glucose）；样品基质：PBS缓冲液、人体血浆/血液样本
检测原理
葡萄糖氧化酶（GOx）作为识别元件，催化葡萄糖氧化并生成过氧化氢（H2O2）。H2O2扩散至铂纳米粒子（Ptnano）表面，在0.6 V施加电位下发生电氧化，产生与H2O2浓度成正比的稳态安培电流。碳纳米管（CNT）导电网络增大电极有效表面积并促进电子传递，胶体金（Aunano）吸附GOx并辅助电子转移，Nafion膜允许底物和产物透过但抑制抗坏血酸、尿酸等干扰。随着葡萄糖浓度升高，酶促反应生成更多H2O2，电流响应增大；表观Michaelis–Menten常数为10.73 mM，表明酶活性保持良好。
检测灵敏度
LOD: 0.4 mM (S/N = 3)；线性范围: 0.5–17.5 mM；相关系数: 0.996；正文另报线性范围: 0.5–16.5 mM；相关系数: 0.992
效应效果
该传感器在无介质条件下对葡萄糖响应迅速，无Nafion时t95%约5 s，Nafion修饰后约7 s且电流损失约20%。Nafion膜显著抑制抗坏血酸（AA）和尿酸（UA）干扰：0.1 mM AA响应由5.4 nA降至0.8 nA，0.5 mM UA由9.6 nA降至1.3 nA；生理浓度下对5.6 mM葡萄糖的干扰比IG+I/IG分别为1.031和1.018。5个电极对1 mM葡萄糖平均响应21 nA，RSD为4.5%。4℃ PBS中储存25 d后仍保留75%初始响应。5份人体血浆/血液样品与医院ASCA AG-II分析仪结果一致，相对误差为-3.5%、+2.8%、-4.4%、+3.8%、+2.4%。表观Michaelis–Menten常数10.73 mM，接近游离酶，表明固定化过程生物相容性好，适合葡萄糖检测。
传感器的构成
- 基底电极：多晶金电极（Au electrode），作为工作电极与导电基底
- 自组装单分子层：半胱胺（cysteamine）SAM，提供末端氨基用于CNT共价连接
- 碳纳米管层：氧化短化多壁碳纳米管（MWNTs/CNTs），经EDC/NHS活化后与SAM形成酰胺键，提供导电网络
- 铂纳米粒子层：Pt nanoparticles（Ptnano），由H2PtCl6电沉积形成，催化H2O2电氧化
- 二硫己醇自组装层：SH(CH2)6SH SAM，修饰Pt纳米粒子表面，用于固定胶体金
- 胶体金层：Au nanoparticles（Aunano），吸附GOx并促进电子转移
- 识别元件：葡萄糖氧化酶（GOx），催化葡萄糖氧化生成H2O2
- 封闭抗干扰层：Nafion 117薄膜，防止GOx流失并抑制AA/UA干扰
中文摘要
开发了一种新型安培葡萄糖生物传感器，基于葡萄糖氧化酶（GOx）吸附于金纳米粒子和铂纳米粒子修饰的碳纳米管（CNT）电极。CNT通过碳二亚胺化学共价固定于金电极，即CNT表面羧基与半胱胺自组装单分子层（SAM）的氨基形成酰胺键。所制备的GOx/Au纳米/Pt纳米/CNT电极覆盖一层薄Nafion，以减少测定中GOx流失并提高抗干扰能力。采用石英晶体微天平（QCM）表征金电极上CNT的固定；扫描电子显微镜（SEM）研究CNT/金和Pt纳米/CNT/金电极形貌；安培法研究金、CNT/金、Pt纳米/金和Pt纳米/CNT/金电极的电化学性能。此外，讨论了Pt纳米粒子电沉积时间、pH值、施加电位和电活性干扰物对传感器安培响应的影响。该酶电极在无介质条件下对葡萄糖表现出优异的电催化活性和快速响应，线性范围为0.5–17.5 mM，校正系数为0.996。该生物传感器用于葡萄糖测定具有良好的重现性和稳定性。
英文摘要
A new amperometric biosensor for glucose was developed based on adsorption of glucose oxidase (GOx) at the gold and platinum nanoparticles-modified carbon nanotube (CNT) electrode. CNTs were covalently immobilized on gold electrode via carbodiimide chemistry by forming amide linkages between carboxylic acid groups on the CNTs and amine residues of cysteamine self-assembled monolayer (SAM). The fabricated GOx/Au(nano)/Pt(nano)/CNT electrode was covered with a thin layer of Nafion to avoid the loss of GOx in determination and to improve the anti-interferent ability. The immobilization of CNTs on the gold electrode was characterized by quartz crystal microbalance technique. The morphologies of the CNT/gold and Pt(nano)/CNT/gold electrodes have been investigated by scanning electron microscopy (SEM), and the electrochemical performance of the gold, CNT/gold, Pt(nano)/gold and Pt(nano)/CNT/gold electrodes has also been studied by amperometric method. In addition, effects of electrodeposition time of Pt nanoparticles, pH value, applied potential and electroactive interferents on the amperometric response of the sensor were discussed. The enzyme electrode exhibited excellent electrocatalytic activity and rapid response for glucose in the absence of a mediator. The linear range was from 0.5 to 17.5mM with correction coefficient of 0.996. The biosensor had good reproducibility and stability for the determination of glucose.