School of Chemistry and Material Sciences, Ludong University, Yantai 264025, China.
ACS Appl Mater Interfaces. 2010 Nov;2(11):3211-6. doi: 10.1021/am1006854. Epub 2010 Oct 28.
The single stranded DNA (ssDNA) with G-rich sequence can fold into G-quadruplex via intramolecular hydrogen-bonding interaction in the presence of ligand. This structure conversion can be specifically detected by a fluorescence method based on different interaction between SYBR Green I (SG) and various DNA structures. SG is proved to intercalate into G-quadruplex and results in high fluorescence intensity, which can be further amplified by 6-fold through fluorescence resonance energy transfer (FRET) from a water-soluble cationic conjugated polymer (CCP) to SG due to the high affinity of positively charged CCP to negatively charged rigid G-quadruplex, whereas it is not performed for ssDNA in the absence of K(+). As a result, the ssDNA/SG/CCP complex can be used to detect potassium ions with improved selectivity in a label-free and cost-effective manner.
单链 DNA（ssDNA）与富含 G 的序列可以在配体存在的情况下通过分子内氢键相互作用折叠成 G-四链体。这种结构转换可以通过一种基于 SYBR Green I（SG）与各种 DNA 结构之间不同相互作用的荧光方法特异性检测。已经证明 SG 嵌入 G-四链体中，导致荧光强度增加，由于带正电荷的 CCP 对带负电荷的刚性 G-四链体具有高亲和力，通过荧光共振能量转移（FRET）从水溶性阳离子共轭聚合物（CCP）到 SG 可以进一步放大 6 倍，而在没有 K（+）的情况下，ssDNA 则不会发生这种情况。因此，ssDNA/SG/CCP 复合物可用于以无标记且经济有效的方式提高选择性地检测钾离子。
