选择性化学发光分子开关阵列对多组分农残的可视化检测

Wide use of pesticides has produced a mass of pesticide residues in environment and agricultural products, which have become a serious danger to ecological environment and human health. Thus there has been a pressing societal need to resolve the challenge in rapid detection of pesticide residues. In this proposal, aiming at the practical need for sensitive detection of multicomponent pesticide residues, our strategy is to develop a novel methodology for building chemiluminescent (CL) switches with intrinsic selectivity on magnetic nanoparticles, in order to overcome the lack of selectivity in traditional CL systems. (1) The CL signal will be produced due to the generation of superoxide on peroxidase-like magnetic nanoparticles, and the CL-enhanced sensing principle and method will be developed based on inhibiting the scavenging of surface radical by molecular binding. (2) We will design the structure and surface recognition molecules of nanoprobes and elucidate the relativity between selective binding of pesticide molecules and CL response signal. After studying sensitivity, selectivity and reliability of various nanoprobes, we will propose the strategies for synthesizing CL nanoprobes with sensitivity to given pesticide molecules. (3) The nanoprobes with different sensitivity will further be assembled into micro/nano chips, and the qualitative and quantitative analysis to multicomponent pesticide residues will be carried out to realize real-time and in situ detecting visualization of trace pesticide residues after combining imaging analysis. The obtained results in this project will provide new theoretical basis and technical fundament for developing portable and low-cost sensor to detect pesticide residues in environment and agricultural products.

农药的广泛使用造成大量农药残留在环境及农产品中，已经给生态环境和人类健康造成严重威胁，国家亟需解决农药残留快速检测所面临的挑战。本研究项目针对多组分农残敏感检测的实际需求，重点克服化学发光自身选择性差的难题，拟在磁性探针表面构建选择性化学发光分子开关。（1）利用磁性粒子的类酶催化特性产生化学发光信号，并根据分子结合抑制表面自由基清除原理（见工作基础），发展化学发光增强型传感原理和方法；（2）通过对探针结构和表面识别基团的设计，阐明纳米探针对农药分子选择性识别与化学发光信号输出的相互关系，建立增强型化学发光分析方法，研究不同探针对农药分子的灵敏性、选择性和可靠性，发展对特定农药分子敏感的探针制备方法；（3）将不同的纳米探针组装成陈列芯片，结合成像分析，建立多组分农残定性定量分析新途径，实现痕量农药残留物实时、原位的可视化检测，为研发便携式、低成本农残检测传感器提供理论基础和技术支撑。

针对农药残留快速检测的难题，该项目提出利用纳米粒子的类酶催化活性，结合化学发光的高敏感特性发展出选择性化学发光分子开关阵列。在项目执行过程中，我们按照任务书开展了类酶活性纳米材料设计，化学发光信号增强方法以及分子开关阵列组装等有关研究工作，最终实现了0.1 nM量级多组分农残的快速可视化检测。(1)纳米金团簇构筑的荧光检测体系：发展了锌离子诱导的共沉淀方法有效去除金团簇溶液中的蛋白质，获得高荧光产率的纯化金团簇体系并据此发展出超敏感的荧光纳米探针，实现了对多种农药的分别响应以及多组分农残的同时可视化检测；针对金纳米团簇对农药分子无响应的困难，设计并制备了高浓度掺杂银的金团簇。这种合金的荧光对除草剂扑灭津表现出超强的“荧光增强”响应，检测限达到0.1 nM，远低于美国环境保护组织规定的残留上限～40 nM。(2)纳米增强的化学发光体系：发展了基于锐钛矿型纳米二氧化钛的增强化学发光体系，利用化学发光高的灵敏性以及表面配体的选择实现了0.1 nM除草剂2,4-D和有机磷农药的快速检测。(3)类酶催化增强的化学发光传感新方法：系统研究了磁性和贵金属纳米粒子的类酶催化活性及其对化学发光的增强效应，发展出抑制自由基清除的传感新方法并在类酶磁性粒子表面构筑了化学发光分子开关，在农药残留高选择性化学发光检测的同时实现实样农产品中的农残检测；进而合成了双功能的金纳米粒子和磁性纳米粒子构成的纳米哑铃，借助于磁性分离和催化增强化学发光效应，构建出选择性检测农药的双功能化学发光探针，检测限达到10 nM。(4)便携式发光仪的研制：基于纳米增强化学发光效应和选择性配体的设计研发出便携式化学发光检测仪，并成功用于水中常见农药有机磷，有机氯的检测，为食品安全及农产品贸易提供了理论和技术支持。上述研究工作取得了多项具有创新性和系统性的研究成果，部分研究工作在高影响力的国际期刊Anal. Chem. 等上发表SCI论文11篇，影响因子全部大于3，并申报国家发明专利1件，培养博士和硕士生5名。申请者还获得安徽省自然科学奖1项（排名第三）。