J Am Chem Soc. 2015 Apr 22;137(15):5149-54. doi: 10.1021/jacs.5b01426. Epub 2015 Apr 14.
Direct, label-free detection of unmodified DNA is a great challenge for DNA analyses. Surface-enhanced Raman spectroscopy (SERS) is a promising tool for DNA analyses by providing intrinsic chemical information with a high sensitivity. To address the irreproducibility in SERS analysis that hampers reliable DNA detection, we used iodide-modified Ag nanoparticles to obtain highly reproducible SERS signals of single- and double-strand DNA in aqueous solutions close to physiological conditions. The phosphate backbone signal was used as an internal standard to calibrate the absolute signal of each base for a more reliable determination of the DNA structure, which has not been achieved before. Clear identification of DNA with single-base sensitivity and the observation of a hybridization event have been demonstrated.
直接、无标记的未修饰 DNA 检测对 DNA 分析来说是一个巨大的挑战。表面增强拉曼光谱（SERS）是一种很有前途的 DNA 分析工具，它可以提供具有高灵敏度的固有化学信息。为了解决 SERS 分析中的重现性问题，该问题阻碍了可靠的 DNA 检测，我们使用碘化物修饰的 Ag 纳米粒子在接近生理条件的水溶液中获得了单链和双链 DNA 的高度重现性 SERS 信号。磷酸骨架信号被用作内部标准，对每个碱基的绝对信号进行校准，从而可以更可靠地确定 DNA 结构，这是以前从未实现过的。已经证明了具有单碱基灵敏度的 DNA 的清晰识别和杂交事件的观察。
