AbstractGold nanoclusters (AuNCs) protected with a bovine serum albumin (BSA) coating are known to emit red fluorescence (peaking at 650 nm) on photoexcitation with ultraviolet light (365 nm). On addition of Cu(II) ions, fluorescence is quenched because Cu(II) complexes certain amino acid units in the BSA chain. Fluorescence is, however, restored if pyrophosphate (PPi) is added because it will chelate Cu(II) and remove it from the BSA coating on the AuNCs. Because PPi is involved in the function of telomerase, the BSA@AuNCs loaded with Cu(II) can act as a fluorescent probe for determination of the activity of telomerase. A fluorescent assay was worked out for telomerase that is highly sensitive and has a wide linear range (10 nU to 10 fM per mL). The fluorescent probe was applied to the determination of telomerase activity in cervix carcinoma cells via imaging. It is shown that tumor cells can be well distinguished from normal cells by monitoring the differences in intracellular telomerase activity. Graphical abstractGold nanoclusters (AuNCs) protected by bovine serum albumin (BSA) and displaying red photoluminescence were prepared as fluorescent probe for the determination of telomerase activity and used for imaging of cervix carcinoma (HeLa) cells.

中文翻译：

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使用 BSA 保护的金纳米团簇作为荧光探针测定癌细胞中端粒酶的活性

摘要 用牛血清白蛋白 (BSA) 涂层保护的金纳米团簇 (AuNCs) 在紫外光 (365 nm) 的光激发下会发出红色荧光（峰值为 650 nm）。添加 Cu(II) 离子后，荧光被淬灭，因为 Cu(II) 与 BSA 链中的某些氨基酸单元复合。然而，如果添加焦磷酸盐 (PPi)，荧光会恢复，因为它会螯合 Cu(II) 并将其从 AuNC 上的 BSA 涂层中去除。由于 PPi 参与端粒酶的功能，负载 Cu(II) 的 BSA@AuNCs 可以作为荧光探针来测定端粒酶的活性。对高度敏感且具有宽线性范围（10 nU 至 10 fM/mL）的端粒酶进行了荧光测定。荧光探针用于通过成像测定宫颈癌细胞中的端粒酶活性。结果表明，通过监测细胞内端粒酶活性的差异，可以很好地将肿瘤细胞与正常细胞区分开来。图形摘要金纳米团簇 (AuNCs) 受牛血清白蛋白 (BSA) 保护并显示红色光致发光，被制备为用于测定端粒酶活性的荧光探针，并用于宫颈癌 (HeLa) 细胞的成像。