The fluorescence quenching properties of Ag-coated Au tetrapod nanostars have been studied via fluorescence spectroscopic techniques. Because of the intense plasmonic light absorption and the corresponding fluorescence resonance energy transfer (FRET), the fluorescence quenching effect of Au tetrapod nanostars could be greatly enhanced by Ag coating. What’s more, the fluorescence quenching ability of Ag-coated Au tetrapod nanostars could be further increased by tuning the size of inner Au tetrapod nanostars or the thickness of the outer Ag coating. In the study of carcinoembryonic antigen (CEA) detection based on the fluorescence probe of Ag-coated Au tetrapod nanostars, surface modification of antibody conjugation has been carried out to guarantee the specificity. Under the optimized conditions, the fluorescence efficiency of the Ag-coated Au tetrapod nanostars probe exhibits a linear response to CEA concentration ranging from 10-280 pg/mL, and the corresponding theoretical detection limit (LOD) is as low as 8.2 pg/mL. Interference experiment results shows that the influence from the interfering proteins could be neglected in the detection, and it has been successfully applied to detect CEA in real samples. Compared with other optical detection techniques of CEA, this method based on fluorescence quenching of Ag-coated Au tetrapod nanostars has better performance because of the special geometry features including regular tips and Ag coating.

已通过荧光光谱技术研究了涂有银的金四足金纳米星的荧光猝灭特性。由于强烈的等离子体吸收和相应的荧光共振能量转移（FRET），Ag涂层可以大大增强金四足金纳米星的荧光猝灭作用。此外，通过调节内部金四足纳米星的大小或外部银涂层的厚度，可以进一步提高涂有银的金四足纳米星的荧光猝灭能力。在基于涂有银的金四足金纳米星的荧光探针的癌胚抗原（CEA）检测研究中，对抗体偶联物进行了表面修饰以确保其特异性。在优化条件下 Ag包覆的Au四足金纳米星探针的荧光效率对CEA浓度表现出线性响应，范围为10-280 pg / mL，相应的理论检测限（LOD）低至8.2 pg / mL。干扰实验结果表明，在检测中可以忽略干扰蛋白的影响，已成功应用于实际样品中CEA的检测。与CEA的其他光学检测技术相比，这种基于Ag包被的Au四足金纳米星的荧光猝灭的方法具有更好的性能，因为它具有规则的尖端和Ag涂层等特殊的几何特征。干扰实验结果表明，在检测中可以忽略干扰蛋白的影响，已成功应用于实际样品中CEA的检测。与CEA的其他光学检测技术相比，这种基于Ag包被的Au四足金纳米星的荧光猝灭的方法具有更好的性能，因为它具有规则的尖端和Ag涂层等特殊的几何特征。干扰实验结果表明，在检测中可以忽略干扰蛋白的影响，已成功应用于实际样品中CEA的检测。与CEA的其他光学检测技术相比，这种基于Ag包被的Au四足金纳米星的荧光猝灭的方法具有更好的性能，因为它具有规则的尖端和Ag涂层等特殊的几何特征。