School of Food Science and Technology, State Key Lab of the Food Science & Technology, Jiangnan University, Wuxi, Jiangsu Province 214122, China.
Nano Lett. 2009 Dec;9(12):4147-52. doi: 10.1021/nl902368r.
Safety of water was for a long time and still is one of the most pressing needs for many countries and different communities. Despite the fact that there are potentially many methods to evaluate water safety, finding a simple, rapid, versatile, and inexpensive method for detection of toxins in everyday items is still a great challenge. In this study, we extend the concept of composites, impregnated porous fibrous materials, such as fabrics and papers, by single-walled carbon nanotubes (SWNTs), toward very simple but high-performance biosensors. They utilize the strong dependence of electrical conductivity through nanotubes percolation network on the width of nanotube-nanotube tunneling gap and can potentially satisfy all the requirements outlined above for the routine toxin monitoring. An antibody to the microcystin-LR (MC-LR), one of the common culprits in mass poisonings, was dispersed together with SWNTs. This dispersion was used to dip-coat the paper rendering it conductive. The change in conductivity of the paper was used to sense the MC-LR in the water rapidly and accurately. The method has the linear detection range up to 10 nmol/L and nonlinear detection up to 40 nmol/L. The limit of detection was found to be 0.6 nmol/L (0.6 ng/mL), which satisfies the strictest World Health Organization standard for MC-LR content in drinking water (1 ng/mL) and is comparable to the detection limit of the traditional ELISA method of MC-LR detection, while drastically reducing the time of analysis by more than an order of magnitude, which is one of the major hurdles in practical applications. Similar technology of sensor preparation can also be used for a variety of other rapid environmental sensors.
水的安全性一直以来都是许多国家和不同社区最紧迫的需求之一。尽管评估水安全的方法有很多，但找到一种简单、快速、通用且廉价的方法来检测日常用品中的毒素仍然是一个巨大的挑战。在这项研究中，我们通过单壁碳纳米管 (SWNTs) 扩展了复合材料的概念，即浸渍多孔纤维材料，如织物和纸张，以开发非常简单但高性能的生物传感器。它们利用通过纳米管渗滤网络的电导率对纳米管-纳米管隧道间隙宽度的强烈依赖性，并且有可能满足上述所有用于常规毒素监测的要求。针对微囊藻毒素-LR (MC-LR) 的抗体，它是大规模中毒的常见罪魁祸首之一，与 SWNTs 一起分散。这种分散体用于蘸涂纸张，使纸张具有导电性。纸张电导率的变化可用于快速准确地检测水中的 MC-LR。该方法的线性检测范围可达 10 nmol/L，非线性检测范围可达 40 nmol/L。检测限发现为 0.6 nmol/L（0.6 ng/mL），满足世界卫生组织对饮用水中 MC-LR 含量的最严格标准（1 ng/mL），与 MC-LR 检测的传统 ELISA 方法的检测限相当，同时将分析时间大大缩短了一个数量级以上，这是实际应用中的主要障碍之一。类似的传感器制备技术也可用于各种其他快速环境传感器。
