具有普适性的表面增强拉曼光谱定量分析技术的研究

Due to the challenges of preparing highly stable and reproducible enhancing media, surface-enhanced Raman spectroscopy (SERS) is primarily a qualitative or semi-quantitative analytical technique, has not yet been adopted as a routine quantitative method. This proposal aims to develop quantitative SERS technique, which includes: 1) investigating the effects of the physical properties of SERS enhancing media (such as the particle size, shape and degree of aggregation of gold and silver nanoparticles) and the laser excitation power and focusing position on the SERS signal of target analytes, and deriving advanced quantitative SERS analysis model from the obtained results; 2) formulating new quantitative SERS analysis strategy based on the established quantitative SERS analysis model to eliminate the detrimental multiplicative effects caused by the variations in the physical properties of SERS enhancing media and the laser excitation power and focusing position on the SERS signal of target analytes; 3) designing and producing SERS enhancing media with quantitative capability under the theoretical guidance of the advanced quantitative SERS analysis model and the new quantitative SERS analysis strategy. The most significant contributions from this research will be to greatly improve the quantitative accuracy of SERS technique and widen its applicability, and hence to upgrade the SERS technique primarily used as a qualitative or semi-quantitative method into a quantitative technique which can be adopted routinely in fields such as biomedical science, food safety and environmental protection.

由于难以获得重现性和稳定性好的增强基底，表面增强拉曼光谱（SERS）目前仅属于定性或半定量分析技术，尚未成为一项成熟的定量分析技术。本项目拟发展和完善SERS定量分析技术，包括：1）弄清SERS基底的物理性质（如：银、金纳米粒子形状、粒径、聚集度等）和激光光源变化对待测物质SERS信号的影响，建立新型SERS光谱定量分析模型；2）发展SERS定量分析新策略，消除SERS基底物理性质和激光光源变化对SERS定量分析结果的影响；3）在SERS定量分析新理论的指导下设计和制备具有准确定量分析功能的SERS基底。本课题的最终研究成果将能够提高SERS技术的普适性及其定量分析结果的精确度，突破传统SERS技术基本上只能进行定性和半定量分析的限制，将其提升为能进行准确定量分析的高检测灵敏度的光谱分析技术，为生物医学、食品安全以及环境保护等研究领域提供重要的定量检测工具，为我国经济建设和社会发展服务。

待测物质的表面增强拉曼光谱（Surface-Enhanced Raman Spectroscopy，SERS）信号的绝对强度不但取决于待测物质的浓度，而且与增强基底的物理性质以及激光光源功率和聚焦位置有关。因此SERS信号的重现性较差，使得目前SERS技术仅属于定性和半定量分析技术，大大削弱了其高检测灵敏度所带来的技术优势，从而严重限制了其应用范围。为了实现应用SERS技术对复杂体系进行准确的定量分析，本项目建立了新型SERS定量分析模型（Multiplicative Effects Model for Surface-Enhanced Raman Spectroscopy－MEMsers），发展了能将待测物质浓度变化所引起的SERS信号贡献与增强基底物理性质等其它因素变化所带来的SERS信号贡献分离开来的方法，并且在新型SERS定量分析模型的理论指导下，设计三种SERS定量检测模式（即，内标加入检测模式、内标标记检测模式、以及广义比率型SERS探针检测模式）及相应的SERS检测基底，实现了多个复杂体系中待测物质的准确SERS定量分析，定量分析结果的平均相对误差均在5%左右, 达到了本项目的预期目的。本项目的研究成果在很大程度上将属于定性分析和半定量分析范畴的SERS技术提升为了准确定量分析技术， 并大大拓展了其应用范围。