Fluorescent adenine (A)‐rich DNA‐templated gold nanoclusters were demonstrated to be a novel probe for determination of biothiols (including cysteine, glutathione, and homocysteine). Fluorescence intensity of adenine‐rich DNA‐templated gold nanoclusters could be greatly quenched by Hg(II) ions through the formation of a gold nanoclusters–Hg(II) system. When biothiols (cysteine as the model) were introduced into the system, the fluorescence intensity recovered due to the formation of a more stable Hg(II)‐thiol coordination complex using Hg‐S metal–ligand bonds, which inhibited the Hg(II)‐mediated fluorescence quenching of adenine‐rich DNA‐templated gold nanoclusters. Based on this fluorescence phenomenon, an on–off–on fluorescence strategy was designed for the sensitive determination of biothiols. The method allowed sensitive detection of cysteine with a linear detection range from 100 nM to 5 μM and a limit of detection of 30 nM. Additionally, the assay can be applied for detection of biothiol levels in human plasma samples. Therefore, it can provide a simple and rapid fluorescent platform for biothiol detection.

中文翻译：

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通过阻止Hg（II）介导的富含腺嘌呤的DNA模板金纳米簇的荧光猝灭来确定生物硫醇的开启荧光策略。

富含荧光腺嘌呤（A）的DNA模板金纳米簇被证明是测定生物硫醇（包括半胱氨酸，谷胱甘肽和高半胱氨酸）的新型探针。富含腺嘌呤的DNA模板金纳米团簇的荧光强度可以通过形成金纳米团簇-Hg（II）系统而被Hg（II）离子极大地淬灭。当将生物硫醇（以半胱氨酸为模型）引入系统时，由于使用Hg-S金属-配体键形成了更稳定的Hg（II）-硫醇配位复合物，从而抑制了Hg（II），荧光强度得以恢复。富腺嘌呤的DNA模板金纳米团簇介导的荧光猝灭。基于这种荧光现象，设计了一种开-关-开荧光策略来灵敏测定生物硫醇。该方法可以灵敏地检测半胱氨酸，线性检测范围为100 nM至5μM，检测极限为30 nM。另外，该测定法可用于检测人血浆样品中的生物硫醇水平。因此，它可以为生物硫醇检测提供简单，快速的荧光平台。