Small water soluble silver nanoclusters (AgNCs) were synthesized either using silver of natural isotopic composition or isotopically enriched silver (^natAgNCs and ¹⁰⁹AgNCs) and employed as labels for specific protein bioimaging. Both types of AgNCs emit a strong fluorescence at 660 nm. Distributions, independently and simultaneously, of metallothioneins 1 and 2 (MT1/2) and superoxide dismutase 1 (SOD1) in human retinal layers from 5 μm thick ocular tissue sections of post-mortem donors were investigated as a proof of concept. For such a purpose, anti-MT1/2 and anti-SOD1 were respectively labelled with ^natAgNCs and ¹⁰⁹AgNCs, and an immunohistochemical protocol was developed. Detection was carried out by fluorescence microscopy and laser ablation (LA) coupled to inductively coupled plasma-mass spectrometry (ICP-MS). In the case of fluorescence microscopy, a high autofluorescence signal was observed at the outer segments of photoreceptors within the retina thus limiting the analytical information in such a region. Additionally, since both types of AgNCs emit at the same wavelength it was not possible to obtain the simultaneous distribution of both proteins by fluorescence microscopy. However, simultaneous specific bioimaging of the two proteins at the same tissue section was possible using both types of AgNCs as labels combined with ICP-MS detection. For such a purpose, the potential of an isotope pattern deconvolution mathematical tool in combination with LA-ICP-MS was successfully evaluated.

中文翻译：

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使用天然和同位素富集的银纳米团簇通过荧光显微镜和激光消融-ICP-MS对生物组织中的蛋白质成像

小的水溶性银纳米团簇（AgNCs）中任一合成使用天然同位素组成的银或同位素富集银（^NAT AgNCs和^109个AgNCs）和用作标签特异性蛋白生物成像。两种类型的AgNC均在660 nm处发出强荧光。作为概念的证明，研究了来自尸体供体5μm厚的人视网膜层中金属硫蛋白1和2（MT1 / 2）和超氧化物歧化酶1（SOD1）的独立和同时分布。为此，将抗MT1 / 2和抗SOD1分别标记为^nat AgNC和¹⁰⁹AgNCs，并开发了一种免疫组织化学方案。通过荧光显微镜和激光烧蚀（LA）耦合到电感耦合等离子体质谱（ICP-MS）进行检测。在荧光显微镜的情况下，在视网膜内感光体的外部部分观察到高的自发荧光信号，因此限制了该区域的分析信息。另外，由于两种类型的AgNC发射相同的波长，因此无法通过荧光显微镜同时获得两种蛋白质的分布。但是，使用两种类型的AgNC作为标记并结合ICP-MS检测，可以在同一组织切片上同时对两种蛋白质进行特定的生物成像。为此目的，