Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, USA.
Anal Chem. 2009 Dec 15;81(24):10002-6. doi: 10.1021/ac901849k.
Aptamers are single-stranded DNA/RNA oligomers that fold into three-dimensional conformations in the presence of specific molecular targets. Surface-enhanced Raman spectroscopy (SERS) of thiol-bound DNA aptamer self-assembled monolayers on Au nanoshell surfaces provides a direct, label-free detection method for the interaction of DNA aptamers with target molecules. A spectral cross-correlation function, Gamma, is shown to be a useful metric to quantify complex changes in the SERS spectra resulting from conformational changes in the aptamer induced by target analytes. While the pristine, unexposed anti-PDGF (PDGF = platelet-derived growth factor) aptamer yields highly reproducible spectra with Gamma = 0.91 +/- 0.01, following incubation with PDGF, the reproducibility of the SERS spectra is dramatically reduced, yielding Gamma = 0.67 +/- 0.02. This approach also allows us to discriminate the response of a cocaine aptamer to its target from its weaker response to nonspecific analyte molecules.
适体是单链 DNA/RNA 寡聚物，在存在特定分子靶标时折叠成三维构象。金纳米壳表面上巯基结合的 DNA 适体自组装单层的表面增强拉曼光谱 (SERS) 为 DNA 适体与靶分子相互作用提供了一种直接、无标记的检测方法。光谱互相关函数 Gamma 被证明是一种有用的度量标准，可以量化由于靶分析物诱导的适体构象变化而导致的 SERS 光谱中复杂变化。虽然原始的、未暴露的抗 PDGF（PDGF = 血小板衍生生长因子）适体产生具有 Gamma = 0.91 +/- 0.01 的高度可重复光谱，但在与 PDGF 孵育后，SERS 光谱的重现性显着降低，产生 Gamma = 0.67 +/- 0.02。这种方法还允许我们区分可卡因适体对其靶标的响应与其对非特异性分析物分子的较弱响应。
