Synthesis of silica-coated gold nanorod as Raman tags by modulating cetyltrimethylammonium bromide concentration
Synthesis of silica-coated gold nanorod as Raman tags by modulating cetyltrimethylammonium bromide concentration
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DOI：
10.1016/j.colsurfa.2012.06.003
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发表时间：
2012-09-05
影响因子：
5.2
通讯作者：
Yang, Tzzy-Schiuan
中科院分区：
文献类型：
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作者：
Huang, Chia-Chi;Huang, Chen-Han;Yang, Tzzy-Schiuan
胶体金纳米棒(AuNRs)作为表面增强拉曼散射(SERS)的衬底，不可避免地要在AuNR表面包覆一层十六烷基三甲基溴化铵(CTAB)。在这里，我们报告了一种改进的制备二氧化硅包覆的金纳米棒作为SERS标签的方法，主要是通过控制CTAB的量来促进合成。通过两次离心法将AuNRs表面的CTAB分子部分去除，使其能够吸附拉曼标记分子，然后重新加入以促进硅壳的生长。在合成过程中，用Zeta电位监测AuNRs的电荷状态。在测定Zeta电位的基础上，结合pH值和CTAB/TEOS摩尔比的影响，提出了CTAB组装物形态变化的模型。利用生物素功能化聚苯乙烯(PS)微球构建的模型探针-靶系统，在24 h内制备了包裹在40 nm厚的圆形二氧化硅外壳中的单个AuNR的SERS标签，并与纳米聚集体标签的SERS信号进行了比较。结果表明，链霉亲和素功能化金标记物在单个PS微球上的表面增强拉曼散射信号与纳米聚集体标记物的SERS信号相当。(C)2012爱思唯尔B.V.保留所有权利。
The applications of colloidal gold nanorods (AuNRs) as substrate for surface-enhanced Raman scattering (SERS) inevitably have to deal with a bilayer of cetyltrimethylammonium bromide (CTAB) around the AuNR surface. Here, we report an improved fabrication of silica-coated gold nanorods as SERS tags by mainly controlling the amount of CTAB to facilitate the synthesis. CTAB molecules on AuNRs were partially removed by centrifugation twice to allow the adsorption of Raman marker molecules and were re-added to promote the growth of silica shells. The zeta potential was used to monitor the charge state of AuNRs during the synthesis. A model of the morphology changes of CTAB assemblies is proposed based on the measurement of zeta potential and effects of pH value and CTAB/TEOS molar ratio. SERS tags with single AuNR enclosed in a round and 40 nm-thick silica shell were produced within 24 h. The SERS signal of a thus-prepared tag was compared with that of a nanoaggregate tag by a model probe-target system made of a biotin-functionalized polystyrene (PS) microsphere. Results showed that the SERS signal from the streptavidin-functionalized AuNR tag on a single PS microsphere is comparable to that from the nanoaggregate-tag counterpart. (C) 2012 Elsevier B.V. All rights reserved.