Toma Sergio H, Santos Jonnatan J, Araki Koiti, Toma Henrique E
Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes, 748, São Paulo, SP, 05508-000, Brazil.
Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes, 748, São Paulo, SP, 05508-000, Brazil.
Anal Chim Acta. 2015 Jan 15;855:70-5. doi: 10.1016/j.aca.2014.12.005. Epub 2014 Dec 6.
A simple and accessible method for molecular analyses down to the picomolar range was realized using self-assembled hybrid superparamagnetic nanostructured materials, instead of complicated SERS substrates such as core-shell, surface nanostructured, or matrix embedded gold nanoparticles. Good signal-to-noise ratio has been achieved in a reproducible way even at concentrations down to 5×10(-11) M using methylene blue (MB) and phenanthroline (phen) as model species, exploiting the plasmonic properties of conventional citrate protected gold nanoparticles and alkylamine functionalized magnetite nanoparticles. The hot spots were generated by salt induced aggregation of gold nanoparticles (AuNP) in the presence of those analytes. Then, the aggregates of AuNP/analyte were decorated with small magnetite nanoparticles by electrostatic self-assembly forming MagSERS hybrid nanostructured materials. SERS peaks were enhanced up to 100 times after magnetic concentration in a circular spot using a magnet in comparison with the respective dispersion of the nanostructured material.
利用自组装混合超顺磁性纳米结构材料，实现了一种简单且易于操作的分子分析方法，该方法可检测低至皮摩尔范围的物质，而无需使用复杂的表面增强拉曼散射（SERS）基底，如核壳结构、表面纳米结构或基质嵌入金纳米颗粒等。以亚甲基蓝（MB）和邻菲罗啉（phen）作为模型物质，即使在浓度低至5×10(-11) M时，利用传统柠檬酸盐保护的金纳米颗粒和烷基胺功能化磁铁矿纳米颗粒的等离子体特性，也能以可重复的方式获得良好的信噪比。在这些分析物存在的情况下，通过盐诱导金纳米颗粒（AuNP）聚集产生热点。然后，通过静电自组装用小磁铁矿纳米颗粒修饰AuNP/分析物聚集体，形成磁SERS混合纳米结构材料。与纳米结构材料的相应分散体相比，使用磁铁在圆形斑点中进行磁浓缩后，SERS峰增强了100倍。
