本文将合成的直径为10 nm的正电荷金纳米颗粒通过静电作用高密度自组装到带负电荷的长链λ-DNA分子上, 形成了高密度的具有纳米间隙的金纳米颗粒网络结构。研究了孤立的金纳米颗粒和所自组装的金纳米颗粒-DNA复合材料作为表面增强拉曼散射(SERS)基底的活性。原本对SERS信号响应较弱的10 nm直径的金纳米颗粒, 在自组装到DNA上形成具有纳米间隙的金纳米颗粒网络后, 产生了均匀、一致、强烈的SERS增强响应。我们利用用该基底对罗丹明G(R6G)、吡啶(Py)和对巯基苯胺(4-ATP)等不同类型的小分子化合物进行SERS检测的结果表明, 此方法制备SERS基底产率高、均一, 具有较好的SERS增强效果好, SERS信号稳定性和重复性相对常规孤立的金纳米颗粒SERS基底有很大提高。

Positively-charged ten-nanometer gold colloidal particles were prepared, and self-assembled to the negatively-charged phosphate groups of the long-chain λ-DNA molecules to form DNA-Au complexes network. This self-assembly resulted in the formation of the high-density nanogaps between the Au nanoparticles absorbed on the DNA molecules, which attributed to the significant enhancement of SERS signal of the Rhodamine 6G molecules. The ten-nanometer gold particles, which are poor at the SERS detection, produced a greatly increase in the SERS sensitivity of R6G detection after the assembly onto the DNA. This study may provide a simple and stable way to produce SERS substrates with a uniform, consistent, and strong SERS enhancement effect by the assembly of metal nanoparticles to DNA molecules.