基于二氧化钛/碳纳米管/壳聚糖纳米复合薄膜制备葡萄糖生物传感器

利用壳聚糖(CHI)溶液分散了纳米二氧化钛(nano-TiO2)和多壁碳纳米管(MWCNT),将该分散液修饰于玻碳电极表面形成纳米复合薄膜;用戊二醛为交联剂在该纳米复合层上固定了葡萄糖氧化酶(GOx),同时以二茂铁为电子媒介体构建了一种新型葡萄糖传感器。利用扫描电镜(SEM)、交流阻抗(AC)对所制备的传感器进行了表征,同时用循环伏安法(CV)和计时电流法(CA)考察了其对葡萄糖的电催化氧化性能。实验结果表明,在优化测试条件下该传感器对葡萄糖在0.5～20.0 mmol.L-1范围内有线性响应,检出限为0.2 mmol.L-1;电流达到95%的稳态时间小于5 s;此生物传感器具有良好的重现性和选择性,能有效排除抗坏血酸、尿酸等常见干扰物的影响并成功应用于饮料中葡萄糖含量的测定。

Preparation of Glucose Biosensor Based on the Nanocomposite Film of Titanium Dioxide/Carbon Nanotubes/Chitosan

A nanocomposite film was prepared by dispersing titanium dioxide nanoparticles (nano-TiO₂) and multi-wall carbon nanotubes (MWCNT) into chitosan (CHI) solution. The glucose oxidase (GOx) was immobilized on this nanocomposite film through cross-linking reactions with glutaraldehyde, and a new glucose sensor was constructed using ferrocene as an electron transfer medium. The prepared sensor was characterized by scanning electron microscope (SEM) and alternating current impedance (AC), and its electrocatalytic performances for glucose were also investigated by cyclic voltammetry (CV) and chronoamperometry (CA). The experimental results showed that the sensor exhibited linear response for glucose in the range of 0.5~20.0 mmol·L^-1 under the optimized testing condition, and the detection limit was 0.2 mmol·L^-1. The current achieved its 95% steady state value within 5 s. This biosensor, which had favorable reproducibility and selectivity, can obviate the influence of the common interferent such as ascorbic acid and uric acid. This sensor was successfully applied to determine the content of glucose in beverage.