Cui Xiaoqiang, Li Chang Ming, Zang Jianfeng, Yu Shucong
School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Dr, Singapore 637457, Singapore.
Biosens Bioelectron. 2007 Jun 15;22(12):3288-92. doi: 10.1016/j.bios.2007.03.004. Epub 2007 Mar 12.
A novel chitosan/PVI-Os(polyvinylimidazole-Os)/CNT(carbon nanotube)/LOD (lactate oxidase) network nanocomposite was constructed on gold electrode for detection of lactate. The composite was nanoengineered by selected matched material components and optimized composition ratio to produce a superior lactate sensor. Positively charged chitosan and PVI-Os were used as the matrix and the mediator to immobilize the negatively charged LOD and to enhance the electron transfer, respectively. CNTs were introduced as the essential component in the composite for the network nanostructure. FESEM (field emission scan electron microscopy) and electrochemical characterization demonstrated that CNT behaved as a cross-linker to network PVI and chitosan due to its nanoscaled and negative charged nature. This significantly improved the conductivity, stability and electroactivity for detection of lactate. The standard deviation of the sensor without CNT in the composite was greatly reduced from 19.6 to 4.9% by addition of CNTs. With optimized conditions the sensitivity and detection limit of the lactate sensor was 19.7 microA mM(-1)cm(-2) and 5 microM, respectively. The sensitivity was remarkably improved in comparison to the newly reported values of 0.15-3.85 microA mM(-1)cm(-2). This novel nanoengineering approach for selecting matched components to form a network nanostructure could be extended to other enzyme biosensors, and to have broad potential applications in diagnostics, life science and food analysis.
一种新型的壳聚糖/聚乙烯基咪唑锇（PVI-Os）/碳纳米管（CNT）/乳酸氧化酶（LOD）网络纳米复合材料被构建在金电极上用于检测乳酸。通过选择匹配的材料组分和优化组成比例对该复合材料进行纳米工程设计，以制备出性能优异的乳酸传感器。带正电荷的壳聚糖和PVI-Os分别用作基质和媒介体，用于固定带负电荷的LOD并增强电子转移。引入碳纳米管作为复合材料中的关键组分以形成网络纳米结构。场发射扫描电子显微镜（FESEM）和电化学表征表明，由于其纳米级尺寸和带负电荷的性质，碳纳米管充当交联剂使PVI和壳聚糖形成网络。这显著提高了检测乳酸的导电性、稳定性和电活性。通过添加碳纳米管，复合材料中不含碳纳米管的传感器的标准偏差从19.6%大幅降低至4.9%。在优化条件下，乳酸传感器的灵敏度和检测限分别为19.7 μA mM⁻¹ cm⁻²和5 μM。与新报道的0.15 - 3.85 μA mM⁻¹ cm⁻²的值相比，灵敏度有显著提高。这种通过选择匹配组分形成网络纳米结构的新型纳米工程方法可扩展到其他酶生物传感器，并在诊断、生命科学和食品分析中具有广泛的潜在应用。
