Wang Tao, Lin Han, Wu Yangbo, Guo Zhiyong, Hao Tingting, Hu Yufang, Wang Sui, Huang Youju, Su Xiurong
State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, State Key Laboratory Base of Novel Functional Materials and Preparation Science, School of Materials Science and Chemical Engineering, Ningbo University, Ningbo, 315211, PR China.
Faculty of Electrical Engineering and Computer Science, Ningbo University, Ningbo, 315211, PR China.
Biosens Bioelectron. 2020 Sep 1;163:112277. doi: 10.1016/j.bios.2020.112277. Epub 2020 May 11.
Electrochemical immunoassay (ECIA) is an important method for rapid, on-site detection of various analytes. However, its detection sensitivity is greatly limited by the traditional sandwich-type sensor construction mode, especially in the case of large-size targets such as pathogenic bacteria with micron size. Herein, we developed a Faraday cage-type sensing mode to build an electrochemical immunosensor based on a functionalized two-dimensional conductive nanomaterial, which could provide a platform to assemble a large number of electrochemical signal labels and a good support for the expansion of electrode surface. Electrons could flow between the electrode and the conductive nanomaterial and then exchange with all signal labels immobilized without the hindrance of non-conductive large-size targets, resulting in a significant signal amplification. In addition, first time integration with fast scan anodic stripping voltammetry (FSASV) allowed for further enhanced ECIA signal. Benefitting from both the Faraday cage-type sensing mode and the high scan rate 100 V s of FSASV, electrochemical signal was effectively amplified several hundred times with a limit of quantitation (LOQ) of 1 CFU mL for micron-sized pathogenic bacteria Vibrio parahemolyticus (VP). This work sheds lights on advancing the design of next-generation ECIA or other redox-related immunoassays with ultrahigh sensitivity, especially for large-size targets.
电化学免疫分析（ECIA）是一种用于快速、现场检测各种分析物的重要方法。然而，其检测灵敏度受到传统夹心型传感器构建模式的极大限制，特别是在检测微米级大小的病原体等大尺寸目标时。在此，我们开发了一种法拉第笼型传感模式，以基于功能化二维导电纳米材料构建电化学免疫传感器，该模式可为大量电化学信号标记物的组装提供平台，并为电极表面的扩展提供良好支撑。电子可在电极与导电纳米材料之间流动，然后与固定的所有信号标记物进行交换，而不会受到非导电大尺寸目标的阻碍，从而实现显著的信号放大。此外，首次将快速扫描阳极溶出伏安法（FSASV）与之结合可进一步增强ECIA信号。受益于法拉第笼型传感模式和FSASV的100 V s高扫描速率，电化学信号被有效放大数百倍，对微米级病原菌副溶血性弧菌（VP）的定量限（LOQ）为1 CFU mL。这项工作为推进下一代超高灵敏度的ECIA或其他与氧化还原相关的免疫分析的设计提供了思路，特别是针对大尺寸目标。
