组成图示
示意图生成中
传感器类型
电化学生物传感器
检测对象
葡萄糖（glucose, Glc）；样品基质：磷酸盐缓冲液、商品葡萄糖注射液、葡萄酒
检测原理
传感器以蛋壳膜为酶固定载体，GOx通过戊二醛与膜蛋白氨基共价交联固定。葡萄糖扩散透过蛋壳膜进入酶层，GOx催化D-葡萄糖与溶解氧反应生成葡萄糖酸和过氧化氢，反应消耗O2。由于蛋壳膜对气体和水分子具有良好透过性，葡萄糖和O2可自由进入酶层，而酶被限制在膜内。溶解氧传感器作为换能器实时监测溶液中O2浓度；葡萄糖浓度越高，单位时间内O2消耗越多，溶解氧下降幅度越大。信号为氧浓度下降值，与葡萄糖浓度呈线性关系。该体系无外加标记物，依靠酶催化循环实现化学计量放大。
检测灵敏度
线性范围: 1.0 × 10−5 to 1.3 × 10−3 mol L−1 glucose；灵敏度斜率: 8.3409 mg L−1 oxygen depletion/mmol L−1 glucose；R^2 = 0.9992
效应效果
传感器响应时间为100 s，对0.50 mmol L−1葡萄糖重复测定RSD为3.26%（n=7）。4 ℃储存4个月后仍保持初始灵敏度的85.2%。乙醇、D-果糖、柠檬酸、苯甲酸钠、蔗糖和L-抗坏血酸等干扰物仅产生轻微葡萄糖当量响应。实际样品中，5%和10%葡萄糖注射液测得4.75%和9.75%（w/v），与商品比色试剂盒（4.91%、9.83%）一致；三种葡萄酒测定值分别为12.5、177和325.4 mmol L−1，与试剂盒12.1、166.8和329.7 mmol L−1相近，加标回收率为90–111%，RSD 1.9–5.9%。作者认为该传感器结构简单、操作方便，适用于实际样品葡萄糖测定。
传感器的构成
- 换能器电极：Pasco CI-6542溶解氧传感器（oxygen sensor），作为氧换能器监测溶解氧浓度变化
- 生物固定膜：蛋壳膜（eggshell membrane, ESM），作为酶固定载体，允许葡萄糖和O2透过
- 识别元件：葡萄糖氧化酶（glucose oxidase, GOx），催化葡萄糖氧化并消耗O2
- 交联固定剂：戊二醛（glutaraldehyde, GA），与ESM和GOx氨基反应实现共价固定
- 反应介质：pH 7.0磷酸盐缓冲液（phosphate buffer, PB），维持酶活性并提供氧电极测量环境
- 装配密封：O形圈（O-ring），将酶固定膜稳定固定在氧传感器表面
- 信号读出：Science Workshop 500接口与计算机，采集、显示和处理溶解氧信号
中文摘要
本文报道了一种基于酶固定蛋壳膜和溶解氧电极的葡萄糖生物传感器。葡萄糖氧化酶（GOx）以戊二醛为交联剂共价固定于蛋壳膜上，再将酶固定蛋壳膜置于溶解氧传感器表面构成传感器。检测方案基于葡萄糖溶液暴露后溶解氧含量下降，并通过监测氧水平降低来关联葡萄糖浓度。文中详细研究了戊二醛浓度、pH、磷酸盐缓冲液浓度和温度对传感器响应的影响。乙醇、D-果糖、柠檬酸、苯甲酸钠、蔗糖和L-抗坏血酸等常见基质干扰物未产生显著干扰。所得传感器响应快（100 s），灵敏度高（8.3409 mg L−1氧耗/mmol L−1葡萄糖），储存稳定性好（4个月后保留初始灵敏度的85.2%），线性范围为1.0×10−5至1.3×10−3 mol L−1葡萄糖。该传感器用于商品葡萄糖注射液和葡萄酒中葡萄糖含量测定，结果与基于比色法的商品葡萄糖试剂盒相当。
英文摘要
A glucose biosensor using an enzyme-immobilized eggshell membrane and oxygen electrode for glucose determination has been fabricated. Glucose oxidase was covalently immobilized on an eggshell membrane with glutaraldehyde as a cross-linking agent. The glucose biosensor was fabricated by positioning the enzyme-immobilized eggshell membrane on the surface of a dissolved oxygen sensor. The detection scheme was based on the depletion of dissolved oxygen content upon exposure to glucose solution and the decrease in the oxygen level was monitored and related to the glucose concentration. The effect of glutaraldehyde concentration, pH, phosphate buffer concentration and temperature on the response of the glucose biosensor has been studied in detail. Common matrix interferents such as ethanol, d-fructose, citric acid, sodium benzoate, sucrose and l-ascorbic acid did not give significant interference. The resulting sensor exhibited a fast response (100s), high sensitivity (8.3409mgL(-1) oxygen depletion/mmolL(-1) glucose) and good storage stability (85.2% of its initial sensitivity after 4 months). The linear response is 1.0x10(-5) to 1.3x10(-3)molL(-1) glucose. The glucose content in real samples such as commercial glucose injection preparations and wines was determined, and the results were comparable to the values obtained from a commercial glucose assay kit based on a spectrophotometric method.