Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, Department of Biochemistry and Molecular Biology, 725 West Lombard Street, Baltimore, MD 21201, USA.
Biochem Biophys Res Commun. 2011 Sep 16;413(1):53-7. doi: 10.1016/j.bbrc.2011.08.042. Epub 2011 Aug 17.
In this article, we report the synthesis strategy and optical properties of a novel type of fluorescence metal nanoshell when it was used as imaging agent for fluorescence cell imaging. The metal nanoshells were made with 40 nm silica cores and 10nm silver shells. Unlike typical fluorescence metal nanoshells which contain the organic dyes in the cores, novel metal nanoshells were composed of Cy5-labelled monoclonal anti-CK19 antibodies (mAbs) on the external surfaces of shells. Optical measurements to the single nanoparticles showed that in comparison with the metal free labelled mAbs, the mAb-Ag complexes displayed significantly enhanced emission intensity and dramatically shortened lifetime due to near-field interactions of fluorophores with metal. These metal nanoshells were found to be able to immunoreact with target cytokeratin 19 (CK19) molecules on the surfaces of LNCAP and HeLa cells. Fluorescence cell images were recorded on a time-resolved confocal microscope. The emissions from the metal nanoprobes could be clearly isolated from the cellular autofluorescence backgrounds on the cell images as either individuals or small clusters due to their stronger emission intensities and shorter lifetimes. These emission signals could also be precisely counted on single cell images. The count number may provide an approach for quantifying the target molecules in the cells.
在本文中，我们报告了一种新型荧光金属纳米壳的合成策略和光学性质，当它被用作荧光细胞成像的造影剂时。这种金属纳米壳由 40nm 的二氧化硅核和 10nm 的银壳组成。与通常含有核内有机染料的典型荧光金属纳米壳不同，新型金属纳米壳由壳外表面上的 Cy5 标记的单克隆抗 CK19 抗体（mAb）组成。对单个纳米粒子的光学测量表明，与无金属标记的 mAb 相比，由于荧光团与金属的近场相互作用，mAb-Ag 复合物显示出显著增强的发射强度和显著缩短的寿命。这些金属纳米壳被发现能够与 LNCAP 和 HeLa 细胞表面的靶角蛋白 19（CK19）分子发生免疫反应。在时间分辨共焦显微镜上记录荧光细胞图像。由于发射强度更强，寿命更短，金属纳米探针的发射可以从细胞的自发荧光背景中清晰地分离出来，无论是单个还是小簇。这些发射信号也可以在单个细胞图像上精确计数。计数数量可能为定量细胞内靶分子提供一种方法。
