基于光纤SERS和微流控的汞离子传感器关键技术研究

Mercury is considered the most important heavy-metal pollutant, because of the likelihood of bioaccumulation and toxicity. It is quite necessary to develop a highly sensitive method for the detection of mercury and its compounds, especially Hg(II) which is a very common state of mercury in the environment. Focusing on the requirements of integration, miniaturization, reproducibility, high sensitivity and real-time, this project will conduct the research on key technologies of the sensor for mercury ion detection based on fiber optical surface enhanced Raman scattering (SERS) and microfluidic. The main research contents are as follows: Sensing mechanism and method for heavy metal ion detection based on SERS; Interaction between heavy metal ion and other object (such as Ag nanoparticles and other tagged molecule) in microfluidic channel; Interaction between exciting light and metal nanoparticles in microfluidic channel; Sensing method and system for reproducible mercury ion detection. The project aims to explore a stable, efficient and universal sensing method for heavy metal ion detection; Establish rapid, uniform microfluidic mixing structure and efficient microfluidic pretreatment unit; Design and manufacture fiber optical coupling structure to further improve the sensitivity of the detection unit; Fabricate droplet generation unit, pretreatment unit, mixing unit and detection unit by using 3D print, MEMS and Microfabrication to obtain the microfluidic sensing system of integration and miniaturization. Take the method for mercury ion detection in this project as a reference, conduct research on the sensing theory and method for other water quality parameters.

汞因其毒性和生物富集特性被认为是一种最重要的重金属污染物。实现快速、经济、灵敏以及精确地测定痕量汞离子在环境保护、食品及生物体安全等领域具有深远意义。本课题将围绕汞离子传感系统的集成化和小型化、可重用性、高灵敏度和高实时性要求，开展基于光纤SERS和微流控的痕量汞离子传感方法与传感器基础问题和关键技术的研究。旨在探索基于SERS的重金属离子识别检测机理，建立高效、普适的重金属离子识别检测方法；阐明微流道内被检测物质与其他物质间作用规律，建立快速、均匀的微流控混合结构以及高效的微流控预处理单元；研究激发光与微流体中金属纳米粒子间作用规律，设计制作进一步提高灵敏度的检测单元光纤耦合结构；采用3D打印、MEMS以及光纤微加工等技术手段完成液滴生成单元、预处理单元、混合单元以及检测单元的制作，并在此基础上实现集成化和小型化的微流控传感系统；以汞离子检测为借鉴，研究其他水质参数传感理论和传感方法。

快速、经济以及精确地测定痕量生化物在环境保护、食品及生物体安全等领域具有深远意义。课题围绕痕量生化物检测系统的集成化、微型化、可重用和高实时性要求，开展光纤微流控SERS传感器关键技术研究。研究了复杂体系结构中的微流体行为规律，探明了微流体在黄金比例螺旋叶片流道结构与微柱阵列流道结构内的混合机制；提出了基于微尺度韦森堡效应直写的工艺方案，探明了微纳尺度下流体微尺度维森堡输运机制，实现了皮升量级高粘度流体(167.5 pL/s, 8 wt% PEO)稳定、快速直写工艺控制，直写出变直径的微流控芯片，为后续微流控检测芯片的制造奠定了基础；提出基于熔体近场静电纺丝的微纳光纤制造方法，改进熔体静电纺丝工艺一步制造出直径和螺距可控的螺旋微纳光纤光栅；探究了微流体中螺旋光纤的荧光信号接收性能，实现了10-8mol/L罗丹明6G的检测，显示出3倍于相同直径微纳光纤的荧光信号接收能力，有望应用于微流控芯片的检测单元；结合微纳3D打印技术实现了微纳光纤-微流控芯片一体化制造；提出基于声化学和机械搅拌的SERS基底制造方法，制备出液态金属纳米草结构的SERS基底，实现了10-7mol/L罗丹明6G的检测，将银纳米粒子与纳米草结构混合，可望实现无特征基团的痕量汞离子检测；设计和制造了集成液滴生成和光纤检测结构的微流控芯片，针对被动混合式连续流微流控芯片的“记忆效应”，采用液滴技术实现油水两相液-液分割，形成微反应液滴，增加微流控传感器的可重用性；将出射光纤和接收光纤按一定拓扑结构嵌入到检测区域，使得拉曼限制区域位于样品限制区域内，消除了流道等干扰物的背景拉曼光谱，提高了检测灵敏度；建立了基于光纤-液滴微流控芯片的通用SERS检测方法，搭建测试系统实现快速、高精度、可重用的痕量生化物SERS检测。