微流控芯片通道内表面增强拉曼（SERS）探测器制备及其检测应用研究

In recent years, brilliant progress in lab-on-a-chip (LoC) systems has unfolded in virtue of its numerous advantages such as low dosage, high safety, high efficiency and high sensitivity compared with conventional macroscopic systems. To date, a variety of detecting methods have been successfully applied in microfuidic systems, among them, laser induced fluorescence has been widely used as a high sensitivity optodetection technique.However, the fluorescence detection methods have been restrained when applied to analytes or products that have no fluorescence. Therefore, fluorescent molecule tagging beforehand is essential for detection. In addition, the fluorescence detection cannot provide sufficient structural information of analytes, which significantly limited their further applications in LoC. Raman spectra provide unique molecular fingerprints composed of many narrow-band peaks corresponding to submolecular vibrational modes in each functional group, making it possible to identify the species of the molecules even facing multiple analytes. SERS has become a powerfulmethod for probing the structural properties of various analytes. Despite the fact that SERS substrates are successfully adopted by LoC systems, there are still a lot of problems in compatibility, efficiency and controllability in real microfluidic analysis. For example, the colloidal SERS substrates might bring significant disturbance to the subsequent reaction and analysis when used in a continuous microflow. Therefore, it is still a challenge to flexibly integrate SERS substrates into the microfluidic channel in a controlled fashion. Here we present a integration of the silver SERS monitor in a ready microfluidic channel for high efficiency target molecule detection. Femtosecond laser induced photoreduction of silver ions will be used for direct fabrication of silver SERS substrates. Novel silver substrates with designable sizes and shapes will be precisely located at any position of the microchannel, indicating the flexibility of this method. As representative tests, p-aminothiophenol, Rhodamine will be used for microfluidic analysis, the SERS mechanism will be explained with FDTD and Gaussian, and portable analysis system on integrated SERS lab-on-a-chip will be prepared.

微流控芯片的表面增强拉曼（SERS）光谱检测由于具有无需标记、对应结构信息、灵敏度高等优点，成为微流控检测有效的补充手段。目前阻碍微流控SERS检测广泛应用的主要原因是缺乏在微流路内进行SERS衬底集成的制备方法，为解决这一问题，本项目提出利用飞秒激光诱导的金属还原和堆积方法在微流通道内制备可选择性定位、局域化、形貌尺寸可控的SERS基底，有望实现微流通道内单分子水平检测。通过研究激光紧聚焦情况下光化学还原的过程，明确各种微观作用力，澄清微结构取向、粗糙度、堆积密度的诱导因素和调控方法，进而实现微流通道内银SERS基底的可控制备；通过置换法或加工金纳米棒方法制备化学稳定性高的金SERS基底；进一步研究该类微流控-SERS芯片的检测功能；并通过数值模拟和理论计算分析SERS增强机理；在此基础上研制高灵敏度的便携式微流控-SERS传感系统。期望本项目研究能够推动微流控芯片SERS检测的实用化。

按照计划已执行完研究内容，具体包括：（1）研究微流通道内的银SERS微纳基底的制备，探索银微纳结构的生长机理；调整加工银盐溶液组分，探索实现复合沉积的可能性，提高检测灵敏度；（2）研究微流通道内优良化学稳定性的金SERS基底的制备，研究置换法在银基底表面包覆金壳，实现致密金壳包覆；研究激光诱导金纳米棒的可控沉积；（3）研究微流控—SERS芯片对各类材料的SERS检测能力（4）揭示SERS增强机制，研制便携式集成的微流控SERS传感系统，通过使用高效SERS基底实现对待测物痕量、快速、实时检测。项目资助下发表SCI论文23篇，参加国内外会议11人次，进行了广泛的合作交流。