聚合物电解质包裹金核银壳纳米棒制备双模式光学细胞成像探针

报道了一种新型的荧光及表面增强拉曼散射(SERS)双模式光学成像探针. 该探针以金核银壳纳米棒为SERS增强基底, 其表面标记拉曼分子产生SERS信号. 随后通过层层吸附的方法在标记了拉曼分子的金核银壳纳米棒表面包裹聚合物电解质. 最后在聚合物电解质层上连接异硫氰酸荧光素产生荧光信号. 将探针置入HeLa细胞, 实现了荧光、SERS双模式成像. 该探针具有以下优点: (1) 能产生荧光、SERS两种信号, 实现双模式光学成像; (2) 金核银壳纳米棒具有优异的SERS增强能力, 使得探针进入活细胞后仍能提供高信噪比的SERS信号; (3) 聚合物电解质在形成隔离层避免荧光信号被金属淬灭的同时, 提高了探针的生物兼容性. 这种双模式光学成像探针在药物输运和肿瘤靶向等研究中具有重大的应用前景.

A dual-mode cell imaging probe based on polyelectrolytes coated Au@Ag core-shell nanorods

A surface enhanced Raman scattering (SERS) and fluorescence dual-mode probe is presented for cell imaging. In the fabrication process of such a probe, SERS reporter molecules were first attached to the surfaces of the Au@Ag core-shell nanorods (Au@AgNRs) to generate SERS signals. Then, the SERS activated Au@Ag NRs were coated with polyelectrolytes (PEs) via the layer-by-layer deposition method. Finally, fluorescein isothiocyanate (FITC) was adsorbed onto the outmost polyelectrolyte layer to generate fluorescence signals. With the designed structure, the proposed probe was capable of generating both SERS and fluorescence signals for cell imaging. The experimental results showed that the Au@Ag NRs can provide excellent SERS enhancing effect, while the PEs layers can protect the fluorescence of FITC from being quenched by the Au@Ag NRs. Furthermore, the PEs layers provided the presented probe with a good biocompatibility. In vitro experiments demonstrated that both SERS and fluorescence images of the living cells can be obtained after being incubated with the probes for 2 h. This kind of dual-mode cell imaging probe has great potential in the design of a drug delivery or tumor targeting nano-system.