Tian Huihui, Li Hongbian, Fang Ying
CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience , National Center for Nanoscience and Technology , Beijing 100190 , China.
University of Chinese Academy of Sciences , Beijing 100049 , China.
ACS Appl Mater Interfaces. 2019 May 1;11(17):16207-16213. doi: 10.1021/acsami.9b02069. Epub 2019 Apr 17.
Surface-enhanced Raman scattering (SERS) can provide fingerprint information of analyte molecules with unparalleled sensitivity. However, quantitative analysis using SERS has remained one of the major challenges owing to the difficulty of obtaining reproducible SERS substrates with high-density hotspots. Here, we report the rational design and fabrication of a binary thiol-capped gold nanoparticle (AuNP) monolayer film (MLF) as a substrate for highly sensitive and quantitative SERS analysis. The two thiol ligands chemically bonded to the AuNPs play different roles: dodecanethiol with a long alkyl chain controls the interparticle gaps and electromagnetic coupling among AuNPs and 4-mercaptopyridine works as a Raman internal standard (IS). The binary thiol-capped AuNPs can self-assemble into an ordered MLF with high-density hotspots and uniformly distributed IS. The as-prepared MLF has been demonstrated as a reliable SERS substrate for quantitative detection of fungicide malachite green in aqueous solution, with a high enhancement factor (up to 3.3 × 10) and a low detection limit (100 pM). Moreover, the MLF SERS substrate is flexible and transparent, which has enabled in situ detection of trace fungicide residues in a shrimp tissue.
表面增强拉曼散射（SERS）能够以无与伦比的灵敏度提供分析物分子的指纹信息。然而，由于难以获得具有高密度热点的可重现SERS基底，使用SERS进行定量分析仍然是主要挑战之一。在此，我们报道了一种二元硫醇封端的金纳米颗粒（AuNP）单层膜（MLF）的合理设计与制备，作为用于高灵敏度和定量SERS分析的基底。化学键合到AuNP上的两种硫醇配体发挥不同作用：具有长烷基链的十二烷硫醇控制AuNP之间的颗粒间间隙和电磁耦合，4-巯基吡啶用作拉曼内标（IS）。二元硫醇封端的AuNP可以自组装成具有高密度热点和均匀分布IS的有序MLF。所制备的MLF已被证明是用于定量检测水溶液中杀菌剂孔雀石绿的可靠SERS基底，具有高增强因子（高达3.3×10）和低检测限（100 pM）。此外，MLF SERS基底是柔性且透明的，这使得能够原位检测虾组织中的痕量杀菌剂残留。
