College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China.
Institute for Materials Discovery, University College London, London WC1H 0AJ, U.K.
Anal Chem. 2024 Nov 5;96(44):17620-17630. doi: 10.1021/acs.analchem.4c03533. Epub 2024 Oct 24.
Conventional solid-based SERS substrates often face challenges with inconsistent sample distribution, while liquid-based SERS substrates are prone to aggregation and precipitation, resulting in irreproducible signals in both cases. In this study, we tackled this dilemma by designing and synthesizing raspberry-like plasmonic nanoaggregates that exhibit a high density of hotspots and are colloidally stable at the same time. In particular, the nanoaggregates consist of a core made of functionalized polystyrene (PS) microspheres, which act as a template for rapid self-assembly of Au@Ag core-shell nanoparticles to form raspberry-like hierarchical nanoaggregates within 5 min of mixing. The optimized nanoaggregates can be used as reproducible and stable SERS substrates for a range of wastewater pollutants (e.g., rhodamine 6G (R6G) and malachite green (MG)) and nucleobases (e.g., adenine and uracil), with the detection limits as low as 1 × 10, 1 × 10, 3 × 10, and 3 × 10 M, respectively. Additionally, the trace detection of adenine in clinical urine samples has been successfully demonstrated. Our modular assembly approach opens up new possibilities in SERS substrate design and advanced trace-chemical detection technologies.
传统的基于固态的 SERS 基底通常面临着样品分布不均匀的挑战，而基于液态的 SERS 基底则容易发生聚集和沉淀，导致在这两种情况下都无法获得可重复的信号。在这项研究中，我们通过设计和合成具有高密度热点且同时具有胶体稳定性的覆盆子状等离子体纳米聚集体来解决这个难题。具体来说，纳米聚集体由功能化聚苯乙烯 (PS) 微球组成的核，在混合 5 分钟内，这些核作为 Au@Ag 核壳纳米粒子快速自组装形成覆盆子状分级纳米聚集体的模板。优化后的纳米聚集体可用作一系列废水污染物（例如，罗丹明 6G（R6G）和孔雀石绿（MG））和核碱基（例如，腺嘌呤和尿嘧啶）的重现性和稳定的 SERS 基底，检测限低至 1×10、1×10、3×10 和 3×10 M 分别。此外，还成功地证明了对临床尿液样本中腺嘌呤的痕量检测。我们的模块化组装方法为 SERS 基底设计和先进的痕量化学检测技术开辟了新的可能性。
