Wang Chenyang, Xu Jingke, Weng Guojun, Li Jianjun, Zhu Jian, Zhao Junwu
The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, No. 28 Xianning West Road, Xi'an, 710049, China.
The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, No. 28 Xianning West Road, Xi'an, 710049, China.
Anal Chim Acta. 2025 Feb 22;1340:343667. doi: 10.1016/j.aca.2025.343667. Epub 2025 Jan 13.
Plasmonic core-shell nanostructures with embedded internal markers used as Raman probes have attracted great attention in surface-enhanced Raman scattering (SERS) immunoassay for cancer biomarkers due to their excellent uniform enhancement. However, current core-shell nanostructures typically exhibit a spherical shape and are coated with a gold shell, resulting in constrained local field enhancement.
In this work, we prepared a core-shell AuNR@BDT@Ag structure by depositing silver on the surface of Raman reporter-modified gold nanorods (AuNR). With cysteamine-driven specific deposition of Ag atoms, the internal standard nanoprobes with an ortho-tetrahedral morphology were obtained. Owing to its tetrahedral morphology and the effective plasmon coupling at the Ag-Au interface, this internal standard Raman probe exhibited excellent Raman enhancement. Also, with embedded Raman reporter, the probes of Au nanorod in Ag tetrahedron avoided the desorption of Raman reporter and competitive adsorption of interfering molecule, which greatly improved the stability and reproducibility of SERS signal and addressed the drawbacks of low reproducibility existing in SERS immunoassay. The feasibility of the AuNR@BDT@Ag probe was demonstrated by the sensitive detection of the liver cancer biomarker alpha-fetoprotein (AFP) in Eppendorf (EP) tubes and microfluidic chips. The results in EP tubes revealed a linear range of 1 fg/mL-1 ng/mL and a detection limit of 0.631 fg/mL. When the detection was performed in microfluidic chips, the linear range was 10 pg/mL to 0.1 μg/mL, with a limit detection of 8.29 pg/mL.
The performance of AFP detection in EP tubes and microfluidic chips demonstrates that the tetrahedral core-shell AuNR@BDT@Ag nanostructures used as internal standard Raman probes have the potential to detect biomarkers in blood samples for cancer screening.
具有嵌入内部标记物的等离子体核壳纳米结构用作拉曼探针，因其出色的均匀增强效果，在癌症生物标志物的表面增强拉曼散射（SERS）免疫分析中备受关注。然而，目前的核壳纳米结构通常呈球形且包覆有金壳，导致局部场增强受限。
在本工作中，我们通过在拉曼报告分子修饰的金纳米棒（AuNR）表面沉积银，制备了一种核壳结构AuNR@BDT@Ag。通过半胱胺驱动的Ag原子特异性沉积，获得了具有正交四面体形态的内标纳米探针。由于其四面体形态以及Ag-Au界面处有效的等离子体耦合，这种内标拉曼探针表现出优异的拉曼增强效果。此外，由于嵌入了拉曼报告分子，Ag四面体中的Au纳米棒探针避免了拉曼报告分子的解吸以及干扰分子的竞争性吸附，极大地提高了SERS信号的稳定性和重现性，解决了SERS免疫分析中存在的重现性低的缺点。通过在Eppendorf（EP）管和微流控芯片中灵敏检测肝癌生物标志物甲胎蛋白（AFP），证明了AuNR@BDT@Ag探针的可行性。EP管中的结果显示线性范围为1 fg/mL - 1 ng/mL，检测限为0.631 fg/mL。当在微流控芯片中进行检测时，线性范围为10 pg/mL至0.1 μg/mL，检测限为8.29 pg/mL。
在EP管和微流控芯片中对AFP的检测性能表明，用作内标拉曼探针的四面体核壳AuNR@BDT@Ag纳米结构有潜力用于检测血样中的生物标志物以进行癌症筛查。
