论文期刊

Growth of Spherical Gold Satellites on the Surface of Au@Ag@SiO2 Core−Shell Nanostructures Used for an Ultrasensitive SERS Immunoassay of Alpha-Fetoprotein




作者: Ying Yang, Jian Zhu,* Jing Zhao, Guo-Jun Weng, Jian-Jun Li, and Jun-Wu Zhao*
发表/完成日期: 2019-01-04
期刊名称: ACS Appl. Mater. Interfaces
期卷:
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论文简介
The identification and detection of cancer biomarkers in early stages is an
important issue for the therapy of cancer. However, most methods are time-consuming
and have limited sensing sensitivity and specificity. In this work, we prepared a novel
plasmonic multilayered core−shell−satellite nanostructure (Au@Ag@SiO2−AuNP)
consisting of a gold nanosphere with a silver coating core (Au@Ag), an ultrathin
continuous silica (SiO2) shell, and a high coverage of gold nanosphere (AuNP)
satellites. The Au@Ag core is a prominent surface enhanced Raman scattering (SERS)
platform, and the thin SiO2 layer exhibits a long-range plasmon coupling between the
Au@Ag core to the AuNP satellites, further leading to enhanced Raman scattering.
Meanwhile, the outer AuNP satellites have a high biocompatibility and long-term
stability. Combining the above advantages, the well-designed metallic nanoassemblies
would be a promising candidate for SERS-based applications in biochemistry. For
specific detection of alpha-fetoprotein (AFP), we utilized the SERS-active core−shell−
satellite nanostructures modified with AFP antibody as immune probes and nitrocellulose membrane (NC) stabilized captured
anti-AFP antibodies as solid substrate. To improve the detection performance, we further systematically optimized the
parameters, including the silver coating thickness of the Au@Ag core and the density and size of the satellite AuNPs. Under the
optimized conditions, AFP could be detected by the SERS-based sandwich immunoassay with an ultralow detection limit of 0.3
fg/mL, and the method exhibited a wide linear response from 1 fg/mL to 1 ng/mL. The limit of detection (LOD) was
considerably lower than conventional methods in the literature. This work relies on the unique Au@Ag@SiO2−AuNP
nanostructures as the immune probe develops a new outlook for the application of multilayered nanoassemblies and
demonstrates the great potential in early tumor marker detection.