Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan.
Anal Bioanal Chem. 2012 Mar;402(9):2827-35. doi: 10.1007/s00216-012-5720-5.
We report the development of a surface plasmon resonance sensor based on the silver ion (Ag(+))-induced conformational change of a cytosine-rich, single-stranded DNA for the detection of Ag(+) and cysteine (Cys) in aqueous solutions. In the free state, single-stranded oligonucleotides fold into double-helical structures through the addition of Ag(+) to cytosine–cytosine (C–C) mismatches. However, in the presence of Cys, which competitively binds to Ag(+), the formation of the C–Ag(+)–C assembly is inhibited, resulting in free-state, single-stranded oligonucleotides. To enhance sensitivity, the DNA intercalator, daunorubicin, was employed to achieve signal enhancement. The detection limit for Ag(+) was 10 nM with a measurement range of 50–2,000 nM, and the detection limit for Cys was 50 nM with a measurement range of 50–2,000 nM. This simple assay was also used to individually determine the spiked Ag(+) concentration in water samples and Cys concentrations in biological fluid samples.
我们报告了一种基于银离子（Ag(+））诱导富含胞嘧啶的单链 DNA 构象变化的表面等离子体共振传感器的开发，用于检测水溶液中的 Ag(+)和半胱氨酸（Cys）。在游离状态下，通过向胞嘧啶-胞嘧啶（C-C）错配中添加 Ag(+)，单链寡核苷酸折叠成双螺旋结构。然而，在存在竞争性结合 Ag(+)的半胱氨酸的情况下，C-Ag(+) - C 组装的形成受到抑制，导致游离状态的单链寡核苷酸。为了提高灵敏度，使用了 DNA 嵌入剂柔红霉素来实现信号增强。Ag(+) 的检测限为 10 nM，测量范围为 50-2000 nM，Cys 的检测限为 50 nM，测量范围为 50-2000 nM。该简单测定法还用于单独测定水样中的加标 Ag(+)浓度和生物流体样品中的 Cys 浓度。
