Ag/mSiO2空心微球的制备及SERS标记性能

Synthesis of Ag/mSiO_2 Hollow Microspheres for SERS-tags

以聚苯乙烯微球为模板,经过原位还原和种子生长过程在聚苯乙烯微球表面包覆银(Ag)纳米粒子;以正硅酸乙酯为硅源,在十六烷基三甲基溴化铵的导向下实现介孔二氧化硅(mSiO2)可控包覆,去除模板得到Ag/mSiO2空心微球.透射电子显微镜(TEM)和氮气吸附-脱附分析结果表明,SiO2壳层厚度约为20 nm,介孔孔径为2.1 nm,孔道分布均匀.进一步利用虹吸作用使对巯基苯胺(4-ATP)分子进入微球内与Ag粒子结合,构建表面增强拉曼散射(SERS)标记材料.SERS测试结果表明,该标记材料检测限达到10-7mol/L,SERS增强因子达到3.7×105.

Ag/mSiO2 hollow microspheres were synthesized via the following steps. Monodisperse polystyrene （PS） colloidal microspheres were coated with Ag nanoparticles through in situ reduction and growing seeds. The composite microspheres were then controllably coated with mesoporous silica shell using cetyl trimethyl ammonium bromide （CTAB） as pore-forming agent. After getting rid of template, Ag/mSiO2 hollow microspheres were obtained. To actualize SERS-tags detection, the hollow microspheres were subsequently tagged with 4-ATP via siphonage effect. Due to the air-resistance effect of mesoporous channel and light＇ s multiple scattering in the interior of hollow microspheres, the obtained SERS-tags material showed low limit of detection and high stability.