Surface-enhanced Raman spectroscopy (SERS) has been successfully used for the label-free detection of single-stranded oligonucleotides. However, the detection of complex DNA secondary structures remains a challenge. Structural features of diverse DNA G-quadruplexes were investigated via a novel SERS method. As a result, a series of highly reproducible and sensitive SERS signatures featuring the structures of G-quadruplexes were obtained. For the first time, we reported remarkably enhanced SERS bands corresponding to purine ring breathing vibrations. Moreover, we observed that by measuring the intensity of the bands corresponding to intramolecular hydrogen bonds, we could quantitatively assess the stability of the G-quadruplexes. Because no labels on DNA strands were present as the experiments were carried out in the solution, the fingerprint peaks reflect the native, internal structure of the G-quadruplexes accurately. The method here detailed provides new insights into the promising applications of diverse DNA structural studies.

中文翻译：

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表面增强拉曼光谱揭示的DNA G四联体的结构特征。

表面增强拉曼光谱（SERS）已成功用于单链寡核苷酸的无标记检测。然而，复杂DNA二级结构的检测仍然是一个挑战。通过新颖的SERS方法研究了多种DNA G四联体的结构特征。结果，获得了一系列具有G-四链体结构的高度可再现和敏感的SERS标记。我们首次报道了与嘌呤环呼吸振动相对应的显着增强的SERS谱带。此外，我们观察到通过测量对应于分子内氢键的条带的强度，我们可以定量地评估G-四链体的稳定性。由于在溶液中进行实验时，DNA链上没有标记，指纹峰准确地反映了G-四链体的天然内部结构。此处详细介绍的方法为各种DNA结构研究的有希望的应用提供了新的见识。