Functional Molecular Materials Research Centre, Scientific Research Academy & School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, P. R. China.
Org Biomol Chem. 2013 Dec 21;11(47):8214-20. doi: 10.1039/c3ob41741g. Epub 2013 Oct 28.
In this work, compound 1 has been rationally designed and synthesized as a new fluorescent probe for biological thiols. Notably, probe 1 has almost no background fluorescence (Φf < 0.0001) in aqueous solutions; however, it exhibited fluorescence turn-on response to thiols with high sensitivity (a 246-fold fluorescence enhancement and a low detection limit of 0.22 μM for Cys). Moreover, probe 1 showed excellent thiol specificity over other biologically relevant species. The kinetic studies indicated that the probe responded to thiols rapidly, and the pseudo-first-order rate constants of probe 1 reaction with Cys, Hcy, and GSH were determined to be 1.85842, 0.67656, and 0.51519 min(-1), respectively. A possible detection mechanism was proposed to involve the Michael addition of the thiol to the α,β-unsaturated ketone, followed by a cleavage of the hemiketal group, thereby leading to the formation of a fluorescent 7-hydroxyl coumarin derivative. Furthermore, the optical responses of probe 1 to thiols were studied by TD-DFT calculations. Finally, probe 1 has been successfully applied to the detection of biological thiols in human blood serum. And the intracellular imaging applications established that probe 1 can be used to detect different concentrations of intracellular thiols in living cells.
在这项工作中，我们合理设计并合成了化合物 1，将其作为一种新的用于生物硫醇的荧光探针。值得注意的是，探针 1 在水溶液中几乎没有背景荧光（Φf < 0.0001）；然而，它对硫醇具有荧光开启响应，灵敏度高（对半胱氨酸的荧光增强 246 倍，检测限低至 0.22 μM）。此外，探针 1 对其他生物相关物种表现出优异的硫醇特异性。动力学研究表明，探针与硫醇快速响应，探针 1 与半胱氨酸、高半胱氨酸和谷胱甘肽反应的拟一级速率常数分别确定为 1.85842、0.67656 和 0.51519 min(-1)。提出了一种可能的检测机制，涉及硫醇与α,β-不饱和酮的迈克尔加成，随后半缩酮基团断裂，从而形成荧光 7-羟基香豆素衍生物。此外，通过 TD-DFT 计算研究了探针 1 对硫醇的光学响应。最后，探针 1 已成功应用于人血清中生物硫醇的检测。并且细胞内成像应用证实，探针 1 可用于检测活细胞中不同浓度的细胞内硫醇。
