NER: Surface-enhanced hyper-Raman scattering for biosensing and bioimaging

该提案是在纳米尺度科学与工程计划（NSF 04-043， NER类别）的响应下收到的。探讨了表面增强超拉曼光谱（SEHRS）的非线性技术在生物分析传感和成像中的应用前景。线性模拟，表面增强拉曼光谱（SERS）是一种众所周知的技术，广泛应用于获得低浓度分析物的振动光谱，在某些情况下低至单分子水平。SERS在包括细胞内检测在内的生物传感应用中被证明是有价值的，但其局限性包括基于拉曼的方法对荧光和样品光降解干扰的通常敏感性。在SEHRS中，红色或近红外激光激发产生近紫外到可见光的拉曼散射，具有许多潜在的优势，包括对荧光的敏感度较低，样品光损伤较小，对感兴趣的分析物有更高的选择性，在成像应用中有更好的空间分辨率，并且由于激发和检测频率之间的巨大差异，能够使用更简单的检测系统。主要的缺点是效果通常较弱。本研究的目标是通过结合拉曼显微镜的小焦点体积和金属纳米粒子表面增强来自本质超拉曼活性发色团的入射和/或散射电磁场来确定这种情况可以缓解的程度。

0507960KelleyThis proposal was received in response to Nanoscale Science and Engineering initiative, NSF 04-043, category NER.The nonlinear technique of surface-enhanced hyper-Raman spectroscopy (SEHRS) will be explored for its possible applications to bioanalytical sensing and imaging. The linear analog, surface-enhanced Raman spectroscopy (SERS) is a well-known technique widely applied for obtaining vibrational spectra of analytes at low concentrations, in some cases down to the single-molecule level. SERS is proving valuable for biological sensing applications including intracellular detection, but its limitations include the usual sensitivity of Raman-based methods to interference from fluorescence and sample photodegradation. SEHRS, in which red or nearinfrared laser excitation produces Raman scattering in the near-uv to visible, has a number of potential advantages including less sensitivity to fluorescence, less sample photodamage, greater selectivity for the analyte of interest, better spatial resolution in imaging applications, and the ability to use a simpler detection system because of the large difference between the excitation and detection frequencies. The main disadvantage is the usual weakness of the effect. The goal of this research is to determine the extent to which this can be mitigated by combining the small focal volume of a Raman microscope with metallic nanoparticle surface enhancement of the incident and/or scattered electromagnetic fields from intrinsically hyper-Raman-active chromophores.