Lu Xiaohui, Ren Wei, Hu Chen, Liu Chenghui, Li Zhengping
Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, Shaanxi Province, People's Republic of China.
Anal Chem. 2020 Sep 15;92(18):12387-12393. doi: 10.1021/acs.analchem.0c02125. Epub 2020 Aug 28.
A single microbead (MB)-concentrated surface-enhanced Raman scattering (SERS) mapping strategy is proposed for ultrasensitive and multiplexed immunoassay with high precision. In this design, the SERS tags are specifically immobilized on the surface of a plasmonic gold nanoparticle (GNP) layer-coated single MB via target protein-mediated immune coupling. By this means, even ultralow target dosage can bring highly concentrated SERS tags on the confined small zone around the single MB, and the target-induced SERS signals are largely enhanced by the plasmonic layer, endowing the proposed strategy with ultrahigh sensitivity to quantify subpicogram per milliliter levels of proteins. Moreover, the per-pixel averaged SERS intensity is adopted for target quantitation through mapping the SERS signals around the MB's surface, achieving greatly improved reproducibility compared with traditional single-point measurement. Benefiting from the intrinsic merits of SERS mapping, this elegant strategy also enables multiplexed immunoassay on a single MB.
提出了一种单微珠（MB）浓缩表面增强拉曼散射（SERS）映射策略，用于超灵敏、多重免疫分析且精度高。在该设计中，SERS标签通过靶蛋白介导的免疫偶联特异性固定在等离子体金纳米颗粒（GNP）层包覆的单个MB表面。通过这种方式，即使超低的靶剂量也能在单个MB周围的受限小区域带来高度浓缩的SERS标签，并且靶诱导的SERS信号被等离子体层大大增强，赋予所提出的策略超高灵敏度以定量每毫升亚皮克水平的蛋白质。此外，通过映射MB表面周围的SERS信号，采用每像素平均SERS强度进行靶定量，与传统单点测量相比，实现了大大提高的重现性。受益于SERS映射的固有优点，这种巧妙的策略还能够在单个MB上进行多重免疫分析。
