Department of Chemistry, University at Albany, SUNY 1400 Washington Avenue, Albany, NY, 12222, USA.
The RNA Institute, College of Arts and Science, University at Albany, SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA.
Sci Rep. 2019 Aug 26;9(1):12356. doi: 10.1038/s41598-019-48650-y.
A two-step process of protein detection at a single molecule level using SERS was developed as a proof-of-concept platform for medical diagnostics. First, a protein molecule was bound to a linker in the bulk solution and then this adduct was chemically reacted with the SERS substrate. Traut's Reagent (TR) was used to thiolate Bovine serum albumin (BSA) in solution followed by chemical cross linking to a gold surface through a sulfhydryl group. A Glycine-TR adduct was used as a control sample to identify the protein contribution to the SER spectra. Gold SERS substrates were manufactured by electrochemical deposition. Solutions at an ultralow concentration were used for attaching the TR adducts to the SERS substrate. Samples showed the typical behavior of a single molecule SERS including spectral fluctuations, blinking and Raman signal being generated from only selected points on the substrate. The fluctuating SER spectra were examined using Principle Component Analysis. This unsupervised statistics allowed for the selecting of spectral contribution from protein moiety indicating that the method was capable of detecting a single protein molecule. Thus we have demonstrated, that the developed two-step methodology has the potential as a new platform for medical diagnostics.
使用 SERS 在单个分子水平上进行蛋白质检测的两步法被开发为用于医学诊断的概念验证平台。首先，将蛋白质分子结合到本体溶液中的连接子上，然后将该加合物与 SERS 基底进行化学反应。Traut's Reagent (TR) 用于在溶液中使牛血清白蛋白 (BSA) 巯基化，然后通过硫醇基团与金表面进行化学交联。甘氨酸-TR 加合物被用作对照样品，以确定蛋白质对 SER 光谱的贡献。金 SERS 基底通过电化学沉积制造。使用超低浓度的溶液将 TR 加合物附着到 SERS 基底上。样品显示了单个分子 SERS 的典型行为，包括光谱波动、闪烁和仅从基底上的选定点产生的 Raman 信号。使用主成分分析检查波动的 SER 光谱。这种无监督统计允许选择来自蛋白质部分的光谱贡献，表明该方法能够检测单个蛋白质分子。因此，我们已经证明，所开发的两步法具有作为医学诊断新平台的潜力。
