Zhang Guannan, Li Junrong, Shen Aiguo, Hu Jiming
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry & Molecular Sciences, Wuhan University, Wuhan, 430072, China.
Phys Chem Chem Phys. 2015 Sep 7;17(33):21261-7. doi: 10.1039/c4cp05343e.
Anisotropic metallic nanoparticles (NPs) possess unique optical properties, which lend them to applications such as surface-enhanced Raman scattering (SERS). However, their preparation by an efficient, biocompatible and high yield synthetic method is still challenging. In this work, we demonstrate a simple and reproducible way to produce chitosan (CS) encapsulated gold-silver nanoflowers by sequentially adding chitosan, chloroauric acid, silver nitrate, and ascorbic acid to water at room temperature. This is a one-pot, seed- and surfactant-free synthetic method, which is simple and credible. CS is used to modulate the size of NPs, while AgNO3 is introduced to improve the monodispersity and homogeneity of NPs. Highly sensitive, spectrally and physically stable SERS tags are developed in virtue of the cooperative effect of CS and Ag(+). Cresyl violet (CV) is applied as a Raman reporter to test the SERS property of NPs, and the results demonstrated that the nanoflowers exhibited stronger and more stable SERS signals than those of spherical gold nanoparticles. Importantly, after being modified by tumor cell-specific targeting ligands (folic acid), the sensitive and stable labeled nanoflowers are applied for cancer cell targeting and SERS imaging.
各向异性金属纳米颗粒（NPs）具有独特的光学性质，这使其适用于诸如表面增强拉曼散射（SERS）等应用。然而，通过高效、生物相容且高产率的合成方法来制备它们仍然具有挑战性。在这项工作中，我们展示了一种简单且可重复的方法，即在室温下依次将壳聚糖（CS）、氯金酸、硝酸银和抗坏血酸添加到水中，从而制备出壳聚糖（CS）包裹的金银纳米花。这是一种无种子、无表面活性剂的一锅法合成方法，简单且可靠。CS用于调节纳米颗粒的尺寸，而引入硝酸银以改善纳米颗粒的单分散性和均匀性。借助CS和Ag(+)的协同效应，开发出了高灵敏度、光谱和物理稳定性良好的SERS标签。将甲酚紫（CV）用作拉曼报告分子来测试纳米颗粒的SERS性能，结果表明纳米花比球形金纳米颗粒表现出更强且更稳定的SERS信号。重要的是，在用肿瘤细胞特异性靶向配体（叶酸）修饰后，这种灵敏且稳定的标记纳米花被用于癌细胞靶向和SERS成像。
