Alexander Troy A, Le Dianna M
U.S Army Research Laboratory, Sensors and Electron Devices Directorate, Optics Branch-Biologically Inspired Devices and Sensors Team, AMSRD-ARL-SE-EO, Adephi, Maryland 20783, USA.
Appl Opt. 2007 Jun 20;46(18):3878-90. doi: 10.1364/ao.46.003878.
Surface-enhanced-Raman-spectroscopy (SERS) can be made an attractive approach for the identification of Raman-active compounds and biological materials (i.e., toxins, viruses, or intact bacterial cells or spores) through development of reproducible, spatially uniform SERS-active substrates. Recently, reproducible (from substrate to substrate), spatially homogeneous (over large areas) SERS-active substrates have been commercialized and are now available in the marketplace. Scanning electron microscopy and high-resolution, tapping-mode atomic force microscopy have been used to analyze these novel plasmonic surfaces for topographical consistency. Additionally, we have assessed, by wavelength-tunable microreflectance spectrometry, the spatial distribution of the localized surface plasmon resonance (LSPR) across a single substrate surface as well as the LSPR lambda(MAX) variance from substrate to substrate. These analyses reveal that these surfaces are topologically uniform with small LSPR variance from substrate to substrate. Further, we have utilized these patterned surfaces to acquire SERS spectral signatures of four intact, genetically distinct Bacillus spore species cultivated under identical growth conditions. Salient spectral signature features make it possible to discriminate among these genetically distinct spores. Additionally, partial least squares, a multivariate calibration method, has been used to develop personal-computer-borne algorithms useful for classification of unknown spore samples based solely on SERS spectral signatures. To our knowledge, this is the first report detailing application of these commercially available SERS-active substrates to identification of intact Bacillus spores.
通过开发可重现、空间均匀的表面增强拉曼光谱（SERS）活性基底，表面增强拉曼光谱（SERS）可以成为一种用于识别拉曼活性化合物和生物材料（即毒素、病毒或完整细菌细胞或孢子）的有吸引力的方法。最近，可重现（从一个基底到另一个基底）、空间均匀（在大面积上）的SERS活性基底已经商业化，现在可以在市场上买到。扫描电子显微镜和高分辨率轻敲模式原子力显微镜已被用于分析这些新型等离子体表面的形貌一致性。此外，我们通过波长可调微反射光谱法评估了单个基底表面上局域表面等离子体共振（LSPR）的空间分布以及不同基底之间LSPRλ（MAX）的变化。这些分析表明，这些表面在拓扑结构上是均匀的，不同基底之间的LSPR变化很小。此外，我们利用这些图案化表面获取了在相同生长条件下培养的四种完整的、遗传上不同的芽孢杆菌孢子物种的SERS光谱特征。显著的光谱特征使得区分这些遗传上不同的孢子成为可能。此外，多元校准方法偏最小二乘法已被用于开发基于个人计算机的算法，该算法仅根据SERS光谱特征就可用于对未知孢子样品进行分类。据我们所知，这是第一份详细报道将这些市售SERS活性基底应用于完整芽孢杆菌孢子鉴定的报告。
