Żygieło Maria, Piotrowski Piotr, Witkowski Marcin, Cichowicz Grzegorz, Szczytko Jacek, Królikowska Agata
Faculty of Chemistry, University of Warsaw, Warsaw, Poland.
Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw, Poland.
Front Chem. 2021 Jun 16;9:697595. doi: 10.3389/fchem.2021.697595. eCollection 2021.
Nanocomposites combining magnetic and plasmonic properties are very attractive within the field of surface-enhanced Raman scattering (SERS) spectroscopy. Applications presented so far take advantage of not only the cooperation of both components but also synergy (enhanced properties), leading to multi-approach analysis. While many methods were proposed to synthesize such plasmonic-magnetic nanoparticles, the issue of their collective magnetic behavior, inducing irreversible self-aggregation, has not been addressed yet. Thus, here we present a simple and fast method to overcome this problem, employing 2-mercaptoethanesulfonate (MES) ions as both a SERS tag and primer molecules in the silica-coating process of the previously fabricated FeO/Ag nanocomposite. The use of MES favored the formation of silica-coated nanomaterial comprised of well-dispersed small clusters of FeO/Ag nanoparticles. Furthermore, adsorbed MES molecules provided a reliable SERS response, which was successfully detected after magnetic assembly of the FeO/Ag@MES@SiO on the surface of the banknote. Improved chemical stability after coating with a silica layer was also found when the nanocomposite was exposed to suspension of yeast cells. This work reports on the application of 2-mercaptoethanesulfonate not only providing a photostable SERS signal due to a non-aromatic Raman reporter but also acting as a silica-coating primer and a factor responsible for a substantial reduction of the self-aggregation of the plasmonic-magnetic nanocomposite. Additionally, here obtained FeO/Ag@MES@SiO SERS nanotags showed the potential as security labels for the authentication purposes, retaining its original SERS performance after deposition on the banknote.
结合磁性和等离子体特性的纳米复合材料在表面增强拉曼散射（SERS）光谱领域非常具有吸引力。迄今为止展示的应用不仅利用了两种成分的协同作用，还利用了协同效应（增强的特性），从而实现多方法分析。虽然已经提出了许多方法来合成这种等离子体磁性纳米颗粒，但它们的集体磁行为导致不可逆的自聚集这一问题尚未得到解决。因此，在这里我们提出一种简单快速的方法来克服这个问题，在先前制备的FeO/Ag纳米复合材料的二氧化硅包覆过程中，使用2-巯基乙磺酸盐（MES）离子作为SERS标签和引物分子。MES的使用有利于形成由分散良好的FeO/Ag纳米颗粒小簇组成的二氧化硅包覆纳米材料。此外，吸附的MES分子提供了可靠的SERS响应，在将FeO/Ag@MES@SiO磁性组装在钞票表面后成功检测到。当纳米复合材料暴露于酵母细胞悬浮液时，还发现用二氧化硅层包覆后化学稳定性得到改善。这项工作报告了2-巯基乙磺酸盐的应用，它不仅由于非芳香拉曼报告分子提供了光稳定的SERS信号，而且还作为二氧化硅包覆引物以及负责大幅减少等离子体磁性纳米复合材料自聚集的因素。此外，这里获得的FeO/Ag@MES@SiO SERS纳米标签显示出作为安全标签用于认证目的的潜力，在沉积在钞票上后保留其原始SERS性能。
