Zhai Yan-Yun, Liu Qian, Cai Wei-Peng, Cao Shuo-Hui, Zhang Li-Xiang, Li Yao-Qun
Department of Chemistry and the MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
J Phys Chem B. 2020 Apr 9;124(14):2760-2768. doi: 10.1021/acs.jpcb.9b11390. Epub 2020 Mar 25.
Simple, stable, easily-fabricated smooth metallic nanofilm can improve the imaging intensity and imaging contrast. However, its application in micrometer-scale cells has not been popularized due to the lack of full understanding of their related fluorescence properties. In this study, fluorescence enhancement of cell imaging on smooth Au nanofilm was investigated over a micrometer-scale range via employment of the optical sectioning method available with a laser scanning confocal fluorescence microscope. The fluorescence enhancement reduced with the distance away from the surface of metallic nanofilm, and this distance dependence was determined by the factors of numerical aperture, dye-substrate distance, and emission wavelength. In addition, distance-dependent fluorescence lifetime images of cells were also measured to study the interaction between fluorophores and metallic film. The enhancement effect of Au nanofilm on fluorescence cell imaging can be induced not only by the standing wave formed by the reflected light and exciting light but also by the interaction between fluorophore and surface plasmons on the metallic nanofilm. Our study on smooth metallic nanofilm should pave the way for utilizing its uniform fluorescence enhancement characteristic for biological imaging.
简单、稳定且易于制备的光滑金属纳米膜可以提高成像强度和成像对比度。然而，由于对其相关荧光特性缺乏全面了解，其在微米级细胞中的应用尚未得到推广。在本研究中，通过使用激光扫描共聚焦荧光显微镜的光学切片方法，在微米级范围内研究了光滑金纳米膜上细胞成像的荧光增强情况。荧光增强随着与金属纳米膜表面距离的增加而降低，这种距离依赖性由数值孔径、染料-底物距离和发射波长等因素决定。此外，还测量了细胞的距离依赖性荧光寿命图像，以研究荧光团与金属膜之间的相互作用。金纳米膜对荧光细胞成像的增强作用不仅可以由反射光和激发光形成的驻波引起，还可以由荧光团与金属纳米膜表面等离子体之间的相互作用引起。我们对光滑金属纳米膜的研究应为利用其均匀荧光增强特性进行生物成像铺平道路。
