电化学生物传感器 2009

Toward real-time continuous brain glucose and oxygen monitoring with a smart catheter.

Biosensors & bioelectronics Li C, Ahn CH, Shutter LA, Narayan RK
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组成图示

Toward real-time continuous brain glu... 传感器构成示意图

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传感器类型

电化学生物传感器

检测对象

葡萄糖(glucose)、氧分压(oxygen partial pressure, pO2/O2);样品基质:脑脊液(cerebrospinal fluid, CSF),拟用于脑细胞外液/脑组织

检测原理

葡萄糖传感器中,葡萄糖氧化酶(GOD)识别葡萄糖并催化其与氧反应生成葡萄糖内酯和过氧化氢(H2O2);H2O2 在铂纳米粒子(Pt NPs)修饰的工作电极上发生电催化氧化,产生与葡萄糖浓度成正比的安培电流。聚烯丙胺(PAA)膜阻挡抗坏血酸、尿酸和对乙酰氨基酚等干扰物,Nafion 外膜稳定酶微环境。氧传感器采用 Clark 三电极构型:O2 在工作电极还原为 OH−,OH− 在对电极氧化再生 O2,实现零净耗氧;Nafion 电解质膜和 RTV 硅胶气膜控制氧扩散,电流随氧分压线性变化。温度传感器提供实时温度,LabView 软件按温度因子和氧分压对葡萄糖/氧信号自动校正,提高体内连续监测准确性。

检测灵敏度

氧传感器:线性范围: 0–60 mmHg;灵敏度: 37.785 nA/mmHg;相关系数: 0.9975;温度灵敏度: 48.7 nA/°C(约3.5%/°C)。葡萄糖传感器:线性范围: 0.1–10 mM;灵敏度: 67.366 nA/mM;R^2 = 0.9995;温度灵敏度: 8.56 nA/°C。

效应效果

IrOx 参比电极在含血 CSF 中 10 天开路电位漂移小于 29.8 mV,pH 4–9 灵敏度为 −64.4 mV/pH。氧传感器在 0–60 mmHg 内线性良好;温度自动校正后,37→30 °C 时误差由 13.6 mmHg 降至 3.4 mmHg。葡萄糖传感器对 2 mM 葡萄糖在生理浓度干扰物下响应比接近 1(AA 1.021、UA 1.013、AP 1.035);温度校正后 37→25 °C 误差由 1.4 mM 降至 0.6 mM,氧分压 151→8.3 mmHg 时误差由 4.3 mM 降至 0.4 mM。临床 CSF 样品与 FreeStyle 血糖仪结果接近,重复测量标准差 0.01–0.03 mM。作者认为该智能导管可用于 TBI 患者脑内实时连续监测。

传感器的构成

  • 基底/柔性电路:Kapton 薄膜(Dupont 100HN)与 PDMS 支撑,承载微电极并卷绕成导管
  • 金属电极层:Ti/Ir/Au(150/500/900 Å)电子束蒸发图案化,作为工作、对、参比电极导电层
  • 葡萄糖传感层:Au 上电化学沉积 Pt 纳米粒子(Pt NPs),增强 H2O2 电催化氧化
  • 抗干扰膜:聚烯丙胺(PAA)/壳聚糖(chitosan)膜,阻挡 AA、UA、AP 等电活性干扰物
  • 识别元件:葡萄糖氧化酶(GOD)固定于壳聚糖基质,经戊二醛(GA)交联,催化葡萄糖生成 H2O2
  • 葡萄糖外膜:Nafion 膜,稳定酶微环境并进一步选择性透过
  • 氧传感层:Nafion 聚合物电解质膜与 RTV 硅胶气体透过膜,构成 Clark 型三电极氧传感器
  • 参比电极:IrOx 修饰 Ir 电极并涂 Nafion,作为生物相容低漂移参比电极
  • 温度传感层:Ti–Ir/Au 金 RTD 与 Parylene 保护,用于温度监测与自动校正

中文摘要

本文设计、制备、表征并优化了用于创伤性脑损伤(TBI)患者实时连续监测的新型智能导管上的氧和葡萄糖生物传感器。氧传感器采用三电极构型,以实现零净耗氧;葡萄糖传感器基于铂纳米粒子增强电极,并用聚阳离子修饰,葡萄糖氧化酶固定于壳聚糖基质中。作者开发了氧化铱(IrOx)电极作为生物相容性参比电极,提高其在生物溶液中的耐久性和稳定性。研究考察了温度对氧传感器性能的影响,以及温度和氧对葡萄糖传感器性能的影响,以增强其运行稳定性并为体内应用提供信息。通过 LabView 编程实现了传感器输出对温度依赖性和氧依赖性的自动校正。在生理和病理生理范围(氧:0–60 mmHg;葡萄糖:0.1–10 mM;温度:25–40 °C)下,使用 TBI 患者临床脑脊液样品进行体外实验,显示测量稳定且准确性提高,表明该传感器可用于实时连续体内监测。

英文摘要

Oxygen and glucose biosensors have been designed, fabricated, characterized and optimized for real-time continuous monitoring on a new smart catheter for use in patients with traumatic brain injury (TBI). Oxygen sensors with three-electrode configuration were designed to achieve zero net oxygen consumption. Glucose sensors were based on the use of platinum nanoparticle-enhanced electrodes that were modified with polycation and glucose oxidase immobilized by chitosan matrix. An iridium oxide electrode was developed to work as a biocompatible reference electrode with enhanced durability and stability in the biological solutions. A study of the effect of temperature on oxygen sensor performance, and both temperature and oxygen effects on glucose sensor performance were accomplished to enhance their operative stability and provide useful information for in vivo applications. A new methodology for automatic correction of the temperature and oxygen dependence of biosensor outputs is demonstrated through programmed LabView software. In vitro experiments in both physiological and pathophysiological ranges (oxygen: 0-60 mmHg; glucose: 0.1-10 mM; temperature: 25-40 degrees C) with clinical samples of cerebrospinal fluid obtained from TBI patients have demonstrated stable measurements with enhanced accuracy, indicating the feasibility of the sensors for a real-time continuous in vivo monitoring.

关键词

葡萄糖生物传感器氧生物传感器智能导管脑脊液创伤性脑损伤电化学