中文摘要：

在环状有机物存在的条件下,Ag＋经激光诱导可发生光还原反应,形成Ag原子聚集的银胶体。本研究通过拉曼散射光谱、紫外-可见光谱和扫描电镜证明,核酸碱基和Ag＋混合溶液经过激光诱导可以生成银胶体颗粒。随着银胶体的生成,核酸碱基的拉曼光谱信号因为表面增强拉曼散射效应而得到明显增强。实验表明,本方法不但可以获得高信噪比的拉曼光谱谱图,而且获得的胞嘧啶、尿嘧啶、胸腺嘧啶、腺嘌呤和鸟嘌呤的增强拉曼光谱与Lee-Meisel银胶和银膜表面两种体系下获得的表面增强拉曼光谱具有相似性。同时,腺嘌呤和鸟嘌呤又出现了一些因Ag＋作用而产生的新位移谱带,但是仍然可以作为指征碱基类别的特征峰归属。利用Ag＋光还原的方法在位获得银溶胶增强拉曼光谱信号,具有银胶制备操作简单、峰位特征等优点,在核酸碱基的低浓度在位检测方面具有应用前景。

英文摘要：

The formation of colloids induced by laser irradiation was proved by the means of Raman scattering,UV-Vis spectrum and transmission electron microscopy（TEM）.The Raman signal of nucleic acid bases was slightly enlarged due to the surface-enhanced Raman scattering activity brought by the aggregation of silver atoms.Furthermore,the experiment results showed that the Raman spectra with high signal to noise ratio and with good repeatability could be obtained by this method and the Raman spectra of nucleic acid bases obtained were similar to those obtained in Lee-Meisel silver colloid and on silver membrane surface.Although there were some new peaks and shifts in our Raman study,the classical characteristic peaks could also be found and used to identify different species.Due to its simple operation,SERS（Surface Enhanced Raman Scattering） of colloids prepared by photo-reduced silver nitrate was of great application value in the in situ detection of small molecules.