State Key Laboratory of Chemo/Biosensing and Chemometrics, Department of Chemistry, Hunan University, Changsha, 410082, People's Republic of China.
Analyst. 2010 May;135(5):1066-9. doi: 10.1039/b925683k.
We report a novel method for biological thiols detection using ssDNA/silver nanoparticles system. The adsorbing ssDNA supplies silver nanoparticles high density charge to rescue nanoparticles from aggregation induced by salt. However, homocysteine (cysteine or glutathione) is conjugated more powerfully than ssDNA to AgNPs via Ag-S bond, which holds back ssDNA binding to AgNPs surface. When salt is added, AgNPs aggregation occurs and the corresponding color changes from yellow to brown after these biological thiols is introduced. A high sensitivity can be achieved using salt as an amplifier to assay thiols. In our study, a favorable linear correlation between the A(0)/A(x) ratio and homocysteine concentration was obtained in the range of 10 to 500 nM with a low detection limit of 10 nM, indicating that homocysteine could be analyzed at low concentration. A concentration as low as 300 nM homocysteine caused a visible color change. As well as, cysteine and glutathione can be detected at a detection limit of 50 nM and 100 nM, respectively. In addition, study on the selectivity of this method shows that only homocysteine, cysteine and glutathione can generate signal response.
我们报道了一种使用 ssDNA/银纳米粒子系统检测生物硫醇的新方法。吸附的 ssDNA 为银纳米粒子提供高密度电荷，以防止盐诱导的纳米粒子聚集。然而，半胱氨酸（半胱氨酸或谷胱甘肽）通过 Ag-S 键比 ssDNA 更有力地与 AgNPs 结合，从而阻止 ssDNA 与 AgNPs 表面结合。当加入盐时，AgNPs 发生聚集，并且在引入这些生物硫醇后，颜色从黄色变为棕色。盐可以作为放大器来检测硫醇，从而实现高灵敏度。在我们的研究中，在 10 到 500 nM 的范围内，A(0)/A(x) 比值与同型半胱氨酸浓度之间获得了良好的线性相关性，检测限低至 10 nM，表明可以在低浓度下分析同型半胱氨酸。浓度低至 300 nM 的同型半胱氨酸会引起可见的颜色变化。此外，半胱氨酸和谷胱甘肽的检测限分别为 50 nM 和 100 nM。此外，对该方法选择性的研究表明，只有同型半胱氨酸、半胱氨酸和谷胱甘肽可以产生信号响应。
