Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Talanta. 2010 Sep 15;82(4):1122-5. doi: 10.1016/j.talanta.2010.06.019. Epub 2010 Jun 23.
An i-DNA based electrochemical proton sensor which is fabricated by attaching the ferrocene-labeled i-DNA (Fc-i-DNA) onto a gold electrode is reported. This type of i-DNA is a cytidine-rich single-stranded oligonucleotide that its conformation can be switched between the random coil conformation and the folded i-motif structure at different pH values. The Fc-i-DNA is thiol terminated and can be bound to the gold electrode surface by Au-S interaction. With the variation of solution pH, the distance between ferrocene moiety and electrode surface is changed, leading to different redox currents. The pH can then be determined by measurement of the corresponding currents. In the range of pH 5.6-7.1, it is shown a linear relationship between the currents and pH values. The proton sensor also exhibits quick response, easy fabrication, and good selectivity.
一种基于 i-DNA 的电化学质子传感器，通过将巯基化的 ferrocene（Fc）标记的 i-DNA（Fc-i-DNA）附着到金电极上而制备。这种 i-DNA 是一种富含胞嘧啶的单链寡核苷酸，其构象可以在不同 pH 值下在无规线团构象和折叠的 i-motif 结构之间切换。Fc-i-DNA 末端带有巯基，可以通过 Au-S 相互作用与金电极表面结合。随着溶液 pH 值的变化，ferrocene 部分和电极表面之间的距离发生变化，导致不同的氧化还原电流。然后可以通过测量相应的电流来确定 pH 值。在 pH 5.6-7.1 的范围内，电流与 pH 值之间呈现线性关系。该质子传感器还表现出快速响应、易于制造和良好的选择性。
