Fitzpatrick Institute for Photonics, Durham, NC 27708, USA.
Department of Biomedical Engineering, Durham, NC 27708, USA.
Analyst. 2022 Jul 12;147(14):3340-3349. doi: 10.1039/d2an00794k.
Solution-based SERS detection by using a portable Raman instrument has emerged as an important tool due to its simplicity, and flexibility for rapid and on-site screening of analyte molecules. However, this method has several shortcomings, including poor sensitivity especially for weak-affinity analyte molecules, where there is no close contact between the plasmonic metal surface and analyte molecule. Examples of weak-affinity molecules include pigment molecules that are commonly used as a consumable coloring agent, such as allura red (AR), and sunset yellow (SY). As high consumption of colorant agents has been shown to cause adverse effects on human health, there is a strong need to develop a simple and practical sensing system with high sensitivity for these agents. Here we present a novel, highly sensitive solution-based SERS detection method for AR, and SY by using CTAC capped gold nanostars (GNS) having different aspect ratios (GNS-2, GNS-4, and GNS-5) without utilizing any aggregating agents which can enhance SERS signal however it reduces batch to batch reproducibility. The influence of the aspect ratio of GNS on SERS properties was investigated. We have achieved a limit of detection (LOD) of AR and SY as low as 0.5 and 1 ppb, respectively by using GNS-5 with the advantages of minimal sample preparation by just mixing the analyte solution into a well plate containing GNS solution. In addition, excellent colloidal stability and reproducibility have further enhanced the applicability in real-world samples. Overall, our results evidence that the solution-based SERS detection platform using high aspect-ratio GNS can be applied for practical application to detect pigment molecules in real samples with satisfactory results.
基于溶液的 SERS 检测方法由于其简单、灵活的特点，可用于快速、现场筛选分析物分子，因此已成为一种重要的工具。然而，这种方法存在一些缺点，包括灵敏度差，特别是对于弱亲和力的分析物分子，因为等离子体金属表面和分析物分子之间没有紧密接触。弱亲和力分子的例子包括通常用作消耗性着色剂的颜料分子，如诱惑红（AR）和日落黄（SY）。由于高消耗的着色剂已被证明对人类健康有不良影响，因此强烈需要开发一种简单实用的高灵敏度传感系统来检测这些试剂。在这里，我们提出了一种新颖的、基于溶液的 SERS 检测方法，用于检测 AR 和 SY，使用具有不同纵横比的 CTAC 封端的金纳米星（GNS）（GNS-2、GNS-4 和 GNS-5），而不使用任何聚集剂，尽管聚集剂可以增强 SERS 信号，但会降低批间重现性。我们研究了 GNS 的纵横比对 SERS 性质的影响。我们使用 GNS-5 实现了 AR 和 SY 的最低检测限（LOD）分别低至 0.5 和 1 ppb，其优点是仅通过将分析物溶液混合到含有 GNS 溶液的微孔板中即可进行最小的样品制备。此外，出色的胶体稳定性和重现性进一步增强了在实际样品中的适用性。总的来说，我们的结果表明，使用高纵横比 GNS 的基于溶液的 SERS 检测平台可以应用于实际应用中，以令人满意的结果检测实际样品中的颜料分子。
