Department of Mechanical Engineering, Columbia University, New York, New York 10027, USA.
ACS Nano. 2013 Jun 25;7(6):5350-9. doi: 10.1021/nn401199k. Epub 2013 Jun 7.
Surface-enhanced Raman spectroscopy (SERS) has been used in a variety of biological applications due to its high sensitivity and specificity. Here, we report a SERS-based biosensing approach for quantitative detection of biomolecules. A SERS substrate bearing gold-decorated silicon nanopillars is functionalized with aptamers for sensitive and specific detection of target molecules. In this study, TAMRA-labeled vasopressin molecules in the picomolar regime (1 pM to 1 nM) are specifically captured by aptamers on the nanostructured SERS substrate and monitored by using an automated SERS signal mapping technique. From the experimental results, we show concentration-dependent SERS responses in the picomolar range by integrating SERS signal intensities over a scanning area. It is also noted that our signal mapping approach significantly improves statistical reproducibility and accounts for spot-to-spot variation in conventional SERS quantification. Furthermore, we have developed an analytical model capable of predicting experimental intensity distributions on the substrates for reliable quantification of biomolecules. Lastly, we have calculated the minimum needed area of Raman mapping for efficient and reliable analysis of each measurement. Combining our SERS mapping analysis with an aptamer-functionalized nanopillar substrate is found to be extremely efficient for detection of low-abundance biomolecules.
表面增强拉曼光谱（SERS）由于其高灵敏度和特异性，已在各种生物应用中得到应用。在这里，我们报告了一种基于 SERS 的生物传感方法，用于定量检测生物分子。一个带有金修饰的硅纳米柱的 SERS 基底通过适体功能化，用于对靶分子进行敏感和特异性检测。在这项研究中，TAMRA 标记的加压素分子在皮摩尔级（1 pM 至 1 nM）范围内通过纳米结构 SERS 基底上的适体特异性捕获，并通过使用自动 SERS 信号映射技术进行监测。从实验结果中，我们通过在扫描区域上积分 SERS 信号强度，在皮摩尔范围内显示出浓度依赖性的 SERS 响应。还注意到，我们的信号映射方法显著提高了统计重现性，并考虑了传统 SERS 定量中的点到点变化。此外，我们开发了一种分析模型，能够预测基底上的实验强度分布，从而可靠地定量生物分子。最后，我们计算了拉曼映射进行有效和可靠分析所需的最小面积。将我们的 SERS 映射分析与适体功能化的纳米柱基底相结合，对于检测低丰度生物分子非常有效。
