Abnormal levels of glutathione (GSH) and glutathione oxidized (GSSG) usually relates to some diseases, thus quantifying the amount of GSH or GSSG is of great significance. A label-free sensing assay based on the enzyme-mimicking property of Cytidine-Au nanoclusters (Cy-AuNCs) was demonstrated for colorimetric detection of GSH, GSSG and glutathione reductase (GR). Firstly, obvious blue color accompanied with an absorption peak at 652 nm was observed due to the high peroxidase-like activity of Cy-AuNCs toward 3,3′,5,5′-tetramethylbenzidine (TMB). Then, in the presence of target, the mimetic activity of Cy-AuNCs could be strongly inhibited and used to achieve the visualization detection. The inhibition effect arose from the surface interaction between GSH and Cy-AuNCs. Linear relationships between absorbance response and concentration were obtained between 0 and 0.4 mM for GSH, 0–2.5 mM for GSSG and 0–0.2 U/mL for GR. The limit of detection (LOD) was calculated as low as 0.01 mM, 0.03 mM and 0.003 U/mL for GSH, GSSG and GR, respectively. Furthermore, the proposed method displayed rapid response, easy procedure and high selectivity.

谷胱甘肽（GSH）和谷胱甘肽氧化（GSSG）的异常水平通常与某些疾病有关，因此定量GSH或GSSG的含量具有重要意义。证明了基于胞苷-Au纳米簇（Cy-AuNCs）的酶模拟特性的无标记传感测定法可用于比色检测GSH，GSSG和谷胱甘肽还原酶（GR）。首先，由于Cy-AuNCs对3,3'，5,5'-四甲基联苯胺（TMB）的高过氧化物酶样活性，观察到明显的蓝色并在652 nm处有吸收峰。然后，在存在靶标的情况下，可以强烈抑制Cy-AuNCs的拟态活性并将其用于可视化检测。抑制作用起因于GSH和Cy-AuNCs之间的表面相互作用。对于GSH，在0至0.4 mM之间，对于GSSG在0至2.5 mM之间，对于GR在0至0.2 U / mL之间，获得了吸光度响应与浓度之间的线性关系。GSH，GSSG和GR的检出限（LOD）分别低至0.01 mM，0.03 mM和0.003 U / mL。此外，该方法具有响应速度快，操作简便，选择性高的特点。