AbstractPoly(3,4-dihydroxy-L-phenylalanine) (polyDOPA) is a stable and biocompatible reducing agent. A versatile strategy is described here for the synthesis of core-shell Au@Ag nanostructures containing a polyDOPA interlayer. The latter provides abundant sites for deposition of nanocomposites, to immobilize molecules and to grow shells. The Au@polyDOPA@Ag nanoparticles are shown to generate strong and stable surface-enhanced Raman spectroscopy (SERS) signals compared to bare AuNPs and bare AgNPs. Folic acid was then immobilized on Au@polyDOPA@Ag nanoparticles and then applied to SERS imaging of human lung adenocarcinoma cell line A549 by the specific recognition of the folic acid receptor. The folic acid-conjugated SERS tags were promising to be nanoplatforms for imaging of cancer cells. Graphical abstractAn Au@Ag core-shell nanostructures SERS nanotag with a polyDOPA interlayer was fabricated and then applied to SERS imaging of epithelial cells. (DOPA: 3,4-Dihydroxy-[L-phenylalanine]; FA: folic acid; 4-MBA: 4-mercaptobenzoic acid).

中文翻译：

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合成具有聚（3,4-二羟基-L-苯丙氨酸）夹层的 Au@Ag 核壳纳米结构，用于上皮细胞的表面增强拉曼散射成像

摘要 聚(3,4-二羟基-L-苯丙氨酸) (polyDOPA) 是一种稳定且具有生物相容性的还原剂。这里描述了一种用于合成含有聚多巴中间层的核壳 Au@Ag 纳米结构的通用策略。后者为纳米复合材料的沉积、固定分子和生长壳提供了丰富的场所。与裸 AuNPs 和裸 AgNPs 相比，Au@polyDOPA@Ag 纳米颗粒显示出产生强而稳定的表面增强拉曼光谱 (SERS) 信号。然后将叶酸固定在 Au@polyDOPA@Ag 纳米颗粒上，然后通过叶酸受体的特异性识别应用于人肺腺癌细胞系 A549 的 SERS 成像。叶酸结合的 SERS 标签有望成为用于癌细胞成像的纳米平台。图形摘要制造了具有聚多巴中间层的 Au@Ag 核壳纳米结构 SERS 纳米标签，然后应用于上皮细胞的 SERS 成像。（多巴：3,4-二羟基-[L-苯丙氨酸]；FA：叶酸；4-MBA：4-巯基苯甲酸）。