分级纳米结构阵列的表面增强拉曼散射效应及对POPs的敏感性

Persistent Organic Pollutants (POPs) pose a big threat to human beings and the environment due to their following characteristics. (1) Resist chemical, biological and photolytic degradation, and persist in for a very long time. (2) Travel long distances in the atmosphere. (3) Bio-magnify as they move up through the food-chain, so even small exposures may eventually reach dangerous levels. (4) Have high toxicity, adverse effects to human health and wildlife. Therefore, rapid detection of trace POPs is very important for our environment protection. Currently large-scale analytical instruments, such as gas chromatography, immunoassays, ion detection technique, and high-resolution mass spectrometry, are commonly used for the analysis of POPs in the laboratory. However, for the above-mentioned analytic instruments, not only it will take very long time (time-consuming) as tedious and complex pre-treatments of the samples have to be carried out for analyzing, but also these large-scale sophisticated instruments in centralized laboratories are not suitable to be moved here and there for field-deployable detection. Therefore developing new sensitive materials and building prototype devices on rapid detection of trace POPs are very exigent..Surface-enhanced Raman scattering (SERS) has a great potential in the rapid detection of trace-level POPs, because it can not only provide the finger-print spectrum of analytes but also enable ultra-sensitive and real-time detection. However, Raman scattering is extremely inefficient because of the small cross-section of Raman scattering. To enable sensitive, label-free, field-deployable detection of POPs by using SERS effect, two key issues must be resolved: (i) a stable and morphologically uniform nanostructured SERS substrate able to greatly amplify Raman signals with good signal reproducibility must be developed; and (ii) the target POPs molecules can be captured from the sample matrix and brought close to the regularly roughened surface of the SERS substrate. However it is difficult to simultaneously achieve these two goals using the current material fabrication methods. .In this project, hierarchical and hybrid nanostructure arrays of noble metal and semiconductor with both high SERS activity and signal reproducibility will be built by using template-assistant approaches in combination with other material synthetic techniques; the specially built high SERS-active nanostructures will be grafted on the surface of the optical fiber probes for field-deployable on-site detection; specific materials with selective absorption of POPs will be modified on the high SERS-active nanostructures to effectively capture POPs for trace detection; prototype devices for rapid detection of trace-level POPs will be constructed. The project will pave the way to the rapid detection of trace POPs, lay foundation on the portable SERS device for real-time on-line detection of ultra-trace POPs, and therefore be important to our eco-environment protection and the human health.

持久性有机污染物(POPs)具有高毒性、生物累积性和半挥发迁移性等，严重危害人类健康。对其进行快速痕量检测至关重要。然而，目前实验室采用的POPs各种分析方法均需要对污染样品进行取样、萃取、浓缩、净化等繁琐的预处理过程，无法实现快速检测。纳米结构的表面能够大幅度增强位于其表面分子的拉曼信号，这种现象称为表面增强拉曼散射(简称SERS)效应。由于拉曼散射光谱具有指纹特性，再加之其测量快速便捷，所以利用纳米结构的SERS效应有望实现对痕量POPs的快速检测。本项目将研究构筑SERS活性高、信号均匀稳定的半导体与贵金属材料的分级纳米结构阵列的方法；将纳米结构修饰在光纤探针的表面；筛选对POPs具有特异性吸附的物质，并将其修饰在纳米结构的表面，以便有效捕捉痕量POPs；研究纳米结构对POPs拉曼信号增强的规律与机理；构建快速检测痕量POPs的原型器件，对突发污染预警跟踪与环境保护具有重要的意义。

持久性有机污染物(POPs)具有高毒性、生物累积性、难降解和半挥发迁移性等，严重危害人类健康和生态环境，对其快速痕量检测至关重要。然而，目前实验室的色谱/质谱等分析方法均需要对样品进行繁琐的前/预处理，无法实现临场快速检测。纳米结构的表面增强拉曼散射(简称SERS)效应能大幅增强位于其表面分子的拉曼信号，且具有指纹特性，测量快速便捷，有望实现对痕量POPs的快速检测。实际中遇到的主要瓶颈是缺少廉价、信号均匀、灵敏度高的SERS检测基片和临场快速检测器件等。针对这些问题，项目研究了具有高SERS活性和信号均匀性的纳米结构基片的设计与构筑的新原理与新方法；对POPs选择性吸附和高灵敏响应的机制；快速检测痕量POPs的原型器件等。项目组紧密围绕申请书和任务书开展研究，圆满完成了任务，实现了预期目标。取得的主要成果包括：①设计构筑了两种金属分级纳米结构及三种有序阵列SERS基片，实现了对蔬果表面农药类POPs的快速痕量检测；②设计构筑了三种半导体/金属异质分级纳米结构阵列SERS基片，实现了对福美双、甲基对硫磷等农药POPs的快速灵敏响应与痕量检测；③设计构筑了四种不同吸附材料与贵金属纳米颗粒组成的复合SERS基片，实现了对多种POPs的选择性捕捉、高灵敏响应与快速痕量检测；④发明了两种基于纳米结构SERS光谱的检测原型器件，实现了对农药类POPs和溶液中带电荷污染物的快速痕量检测。发表SCI论文21篇；申请发明专利18件（已授权11件）；成果作为“拉曼光谱快速检测毒品毒物的增强基片、方法及仪器的关键技术”的部分内容，获2020年度国家技术发明二等奖。上述成果的取得，为环境中POPs的快速痕量检测提供了科学依据、奠定了核心关键材料和技术基础，对保护环境和建设美丽中国具有重要意义。另外，项目执行期间，已培养毕业博士5名，在读博士4名、硕士2名，为该领域的发展培养了多名青年骨干人才。