基于表面展示微生物的黄曲霉毒素电化学传感器信号响应机制的研究

Aflatoxins (AFs) are a group of highly toxic and carcinogenic secondary metabolites, which can pose severe hazards to environmental and food safety. Aim to develop an efficient and quantitative AFs detection method, firstly, we proposed to develop a genetically modified microorganism for sensing Afs by surface displaying Aflatoxin oxidase on the outside cell membrane. Then, this microorganism was integrated with bioelectrochemical system to develop a fast-response and quantitative AFs biosensor, which is able to convert AFs signals to electric current signal directly. This project mainly focuses on exploring the signal response mechanism at the interface of bacterium/AFO/electrode. Furthermore, to enhance the signal transmission and conversion, two electron transfer pathway between the AFO and the electrode will be built to improve the electron transfer. One is direct electron transfer pathway based on covalent bonding between the AFO and the electrode. While the other one is mediated electron transfer pathway using soluble electron mediators. Based on these work, the performance of AFO surface-displayed microorganism based AF bioelectrochemical sensor can be improved. Our work can provide a potential platform for developing novel biosensors with high specificity and stability, which are important for environmental pollution detection and food safety monitoring.

黄曲霉毒素（AFs）是一种强致癌的毒性物质，它严重威胁环境安全与食品安全。本项目针对定量检测AFs中存在的难题，首先，通过微生物表面展示技术构建黄曲霉毒素氧化酶（AFO）表面展示微生物，并进而将该AFO表面展示微生物与微生物电化学系统（BES）相整合构建可以定量、快速检测AFs的微生物电化学传感器，从而实现AF浓度到电流信号的直接转化和AFs的定量检测。本项目将重点针对该体系中存在的微生物/AFO/电极微观界面上的信号响应及传递机制进行研究。并在此基础上，从AFO/电极之间的电子传递过程入手，通过在两者之间构建直接或间接的电子强化传递途径，从而强化信号响应和传输，最终实现该基于AFO表面展示微生物的AFs传感器性能优化的目的。该项目的研究结果将为构建具有特异性信号传感功能的微生物电化学传感器提供一个技术平台和理论支持，在环境污染检测和食品安全控制方面具有理论和应用价值。

黄曲霉毒素（AFs）是一种强致癌的毒性物质，它严重威胁环境安全与食品安全。本项目针对传统定量检测AFs的测试方法与酶传感器存在的问题，开展了一系列研究。首先，利用表面展示技术构建了表面展示黄曲霉毒素氧化酶（AFO）的酵母，使得AFO在酵母表面稳定地表达，并可以产生足够的AFO表达量确保后续的感应信号强度。进而，利用表面引发原位聚合技术构建微生物印记聚合物修饰电极，利用该电极对表面电荷分布与印记微生物相似的微生物具有选择性，最大程度上确保生物电极表面功能微生物的稳定。在前两部分工作的基础上，构建基于微生物电化学系统和微流控芯片的AFs的生物传感器。该传感器可利用循环伏安法可对1.25-25.0 ppm范围内的AFs进行准确定量分析，最低监测限可达0.25 ppm。本研究开发的基于微生物电化学系统的AFs传感器具有响应时间短，感应准确，信号易于读取，操作方便等优点，可以为AFs的快速检测提供新的思路和方法。