以柠檬酸钠为还原剂制备了5种金-银合金纳米溶胶, 并利用扫描电镜 (SEM)和紫外-可见光谱(UV-Vis)对5种合金纳米粒子进行表征。SEM显示5种金-银合金纳米粒子基本呈球形结构, 其粒径在15～50 nm之间, 纳米粒子尺寸随金的摩尔分数的增加, 粒径减小。紫外-可见光谱显示, 随金含量的不同, 纳米粒子的等离子共振峰(SPR)出现红移现象, 说明金-银纳米粒子SPR峰具有可调性。以5种金-银合金纳米溶胶作为活性基底, 测定了血清的表面增强拉曼光谱。结果显示, 以金-银合金纳米溶胶作为活性基底的血清拉曼光谱中, 不但蛋白质分子的谱峰极大增强, 而且检测到了血清中含量非常低的脂类和多糖光谱。实验结果表明金-银合金纳米溶胶是血清SERS优良的活性基底。

Five kinds of Au-Ag alloy nanoparticles were prepared by using sodium citrate as reducing agent. Five kinds of alloy nanoparticles were characterized by scanning electron microscopy (SEM)and ultraviolet visible spectroscopy (UV-Vis). SEM showed that the five kinds of Au-Ag alloy nanoparticles were spherical in shape, and the particle size was between 15～50 nm, the size of nanoparticles decreased with the increase of mole fraction of gold. The UV -Vis spectra showed that the surface plasma resonance peak (SPR)of the nanoparticles appeared red shift with the different content of gold, which indicated that the SPR peak of Au-Ag nanoparticles were tunable. The surface enhanced Raman spectra of the serum were measured by using five kinds of Au-Ag alloy nanoparticles as active substrate. The results showed that in serum Raman spectra of Au-Ag alloy nanoparticles as active substrates, not only the spectral peak of protein molecules was greatly enhanced, but also the very low lipids and polysaccharides spectra were detected. The results show that Au-Ag alloy nanoparticles is an excellent active substrate for serum SERS.