State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, PR China.
Biosens Bioelectron. 2013 Jan 15;39(1):268-73. doi: 10.1016/j.bios.2012.07.058. Epub 2012 Aug 5.
An effective G-quadruplex-based probe has been constructed for rapid and sensitive detection of Cu(2+). In this probe, an anionic porphyrin, protoporphyrin IX (PPIX) served as a reference signal, which binds to G-quadruplex specifically and the fluorescence intensity increases sharply. While, in the presence of Cu(2+), the G-quadruplex can catalyze the related Cu(2+) insertion into the protoporphyrin, the fluorescent intensity is decreased. The fluorescence of the response ligand could be selectively quenched in the presence of Cu(2+) and not interfered by other metal ions. The probe provided an effective platform for reliable detection of Cu(2+) with a detection limit as low as 3.0nM, the high sensitivity was attributed to the strong metalation of PPIX with Cu(2+) catalyzed by G-quadruplex (PS5.M). Linear correlations were obtained over the logarithm of copper ion concentration in the range from 8×10(-9)M to 2×10(-6)M (R=0.998). The G-quadruplex-based probe also could be used to detect Cu(2+) in real water samples. Additionally, these striking properties endow the G-quadruplex-ligand with a great promise for analytical applications.
一种基于 G-四链体的有效探针已被构建，用于快速灵敏地检测 Cu(2+)。在该探针中，阴离子卟啉原 IX（PPIX）作为参考信号，它特异性地与 G-四链体结合，荧光强度急剧增加。然而，在存在 Cu(2+)的情况下，G-四链体可以催化相关的 Cu(2+)插入到原卟啉中，荧光强度降低。响应配体的荧光可以在存在 Cu(2+)时被选择性猝灭，而不受其他金属离子的干扰。该探针为可靠检测 Cu(2+)提供了有效的平台，检测限低至 3.0nM，高灵敏度归因于 G-四链体（PS5.M）催化的 PPIX 与 Cu(2+)的强金属化。在 8×10(-9)M 至 2×10(-6)M 的铜离子浓度对数范围内，获得了线性相关（R=0.998）。基于 G-四链体的探针还可用于检测实际水样中的 Cu(2+)。此外，这些显著的性质使 G-四链体配体在分析应用中具有很大的应用前景。
