基于Ag/Si-NPA的DNA碱基高灵敏度SERS探测

Highly Sensitive SERS Detection of DNA Bases Realized by Silver/Silicon Nanoporous Pillar Array

以硅纳米孔柱阵列(Si-NPA)为衬底,采用浸渍还原法制备了一种图案化的硅基银纳米结构(Ag/Si-NPA).以Ag/Si-NPA为表面增强拉曼散射(SERS)的活性基底,实现了对鸟嘌呤、胞嘧啶和胸腺嘧啶三种DNA碱基的低浓度探测.结果表明,三种DNA碱基分子均通过羰基和氮原子倾斜吸附于Ag/Si-NPA表面且吸附位点类似,但倾斜角略有不同.随着溶液浓度的降低,碱基分子更趋向平行吸附于基底表面.由此证明,Ag/Si-NPA可以显著增强DNA碱基分子的拉曼散射效应,是一种可用于低浓度生物分子检测的性能优异的SERS活性基底.

A regularly patterned silver nanostructure(Ag/Si-NPA)was prepared by an immersion plating method on the template of silicon nanoporous pillar array(Si-NPA).Using Ag/Si-NPA as active substrates,the adsorption behavior of three DNA bases(guanine,cytosine,and thymine)at low concentration was studied by surface-enhanced Raman scattering(SERS)technique.Based on the obtained SERS spectra,it was deduced that the three DNA bases were all slightly tilted adsorbed on the surface of the silver particles but with different inclination angles.The adsorption sites for different bases were similar:all through carbonyl group and nitrogen atom.With reducing concentration,the planes of the base molecules were all tend to be parallel to the surface of substrate.The results suggested that the Raman spectra of DNA bases could be significantly enhanced when adsorbed on the surface of Ag/Si-NPA,and it might be an effective SERS active substrate for the detection of low-concentration bio-molecules.