State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China.
Department of Chemistry, University of California-Riverside, California, 92521, United States.
Anal Chim Acta. 2019 May 30;1057:1-10. doi: 10.1016/j.aca.2018.12.061. Epub 2019 Jan 9.
We prepared an ultrathin porous silica shell-coated Au-Ag alloy nanoparticle (AuAg@p-SiONP) and developed it as a novel alkyne-based surface-enhanced Raman scattering (SERS) nanoprobe for the ratiometric Raman imaging of exogenous and endogenous HO in live cells. The AuAg@p-SiONPs functionalized with 4-mercaptophenylboronic acid (MPBA) and 4-mercaptophenylacetylene (MPAE, 1986 cm) as internal standard were first incubated with dopamine (DA) to incorporate the bridging molecules through the formation of borate bond between DA and MPBA on the surface of nanoparticle. Then, the signaling alkyne molecules of 3-(4-(phenylethynyl) benzylthio) propanoic acid (PEB, 2214 cm) were conjugated to the surface of nanoparticle through the formation of amide bond between the carboxyl group on the PEB and the amino group on the DA, forming the ratiometric SERS nanoprobe. In the presence of HO, the alkynyl on the PEB is released from the surface of the Au-Ag alloy nanoparticle due to the boronate-to-phenol switch, decreasing the Raman signal at 2214 cm significantly. Since the Raman signal of MPAE at 1986 cm remains unchanged, quantitative analysis of HO concentration can be achieved based on the ratiometric value of I/I. Under the optimized conditions, the plot of the ratiometric value of I/I versus the HO concentration in the range from 0.12 to 8 μM revealed a good linear response with a detection limit of 52 nM based on a signal-to-noise ratio of S/N = 3. The porous SiO-coated Au-Ag alloy nanoparticle provides a novel SERS substrate with excellent biocompatibility, high stability, and effective anti-interference ability. Together with the alkynyl derivatives as internal standard, the SERS nanoprobe reported here allows the ratiometric detection of HO in live cells and can be further applied to quantify many other biomolecules by using different signaling agents.
我们制备了一种超薄多孔硅壳包覆的金-银合金纳米粒子（AuAg@p-SiONP），并将其开发为一种新型基于炔烃的表面增强拉曼散射（SERS）纳米探针，用于活细胞中外源和内源性 HO 的比率型拉曼成像。首先，用 4-巯基苯硼酸（MPBA）和 4-巯基苯乙炔（MPAE，1986cm）官能化的 AuAg@p-SiONP 作为内标与多巴胺（DA）孵育，通过 DA 与纳米粒子表面上的 MPBA 之间形成硼酸酯键来掺入桥接分子。然后，通过 PEB 上的羧基与 DA 上的氨基之间形成酰胺键，将信号炔烃分子 3-（4-（苯乙炔基）苄硫基）丙酸（PEB，2214cm）接枝到纳米粒子表面，形成比率型 SERS 纳米探针。在 HO 的存在下，由于硼酸酯到苯酚的开关，PEB 上的炔基从 Au-Ag 合金纳米粒子表面释放出来，导致 2214cm 处的 Raman 信号显著降低。由于 1986cm 处的 MPAE 的 Raman 信号保持不变，因此可以基于 I/I 的比率值进行 HO 浓度的定量分析。在优化条件下，I/I 比率值与 0.12 至 8μM 范围内 HO 浓度的关系图呈现出良好的线性响应，检测限为 52nM，基于信噪比 S/N=3。多孔 SiO 包覆的 Au-Ag 合金纳米粒子提供了一种具有优异生物相容性、高稳定性和有效抗干扰能力的新型 SERS 基底。与炔基衍生物作为内标一起，这里报道的 SERS 纳米探针允许对活细胞中的 HO 进行比率型检测，并可以通过使用不同的信号剂进一步用于定量检测许多其他生物分子。
