文章基本信息

标题：A label-free fluorescent probe for Hg2+ and biothiols based on graphene oxide and Ru-complex
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作者：Linlin Wang ; Tianming Yao ; Shuo Shi 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2015
卷号：4
期号：1
DOI：10.1038/srep05320
语种：English
出版社：Springer Nature
摘要：A novel, selective and sensitive switch-on fluorescent sensor for Hg²⁺ and switch-off fluorescent probe for biothiols was developed by using [Ru(bpy)₂(pip)]²⁺ as the signal reporter and graphene oxide (GO) as the quencher. Due to the affinity of GO towards single-stranded DNA (ss-DNA) and [Ru(bpy)₂(pip)]²⁺, the three components assembled, resulting in fluorescence quenching. Upon addition of Hg²⁺, a double-stranded DNA (ds-DNA) via T–Hg²⁺–T base pairs was formed, and [Ru(bpy)₂(pip)]²⁺ intercalated into the newly formed ds-DNA. Then, [Ru(bpy)₂(pip)]²⁺ and ds-DNA were removed from the surface of GO, resulting in the restoration of fluorescence. Subsequently, upon addition of biothiols, Hg²⁺ was released from ds-DNA, due to the higher affinity of Hg²⁺ to the sulfur atoms of biothiols, which could induce ds-DNA unwinding to form ss-DNA. Then ss-DNA and [Ru(bpy)₂(pip)]²⁺ were adsorbed on the surface of GO, the fluorescence of [Ru(bpy)₂(pip)]²⁺ was quenched again. Therefore, the changes in emission intensity of [Ru(bpy)₂(pip)]²⁺ directly correlated to the amount of detection target (Hg²⁺ or biothiols) in solution. The assay exhibited high sensitivity and selectivity, with the limits of detection for Hg²⁺, cysteine (Cys) and glutathione (GSH) to be 2.34 nM, 6.20 nM and 4.60 nM, respectively.