Department of Physical and Environmental Sciences, University of Toronto Scarborough, 11265 Military Trail, Toronto, M1 C 1 A4, Canada.
Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, M5S 3H6, Canada.
Chempluschem. 2021 Feb;86(2):224-231. doi: 10.1002/cplu.202000607. Epub 2020 Oct 13.
Herein, the consecutive incorporation of Ag ion into the dsDNA containing adjacent C-C mispairs is demonstrated. The melting temperature (T ) was 8 C higher for DNA containing three C-C mispairs upon the addition of three Ag ions as compared to the Ag -free DNA, and no T was obtained in the presence of excess Ag ion, indicating a stable bridging of C-Ag -C upon the incorporation of the stoichiometric amount of Ag per C-C mispair. The circular dichroism (CD) spectra of the dsDNA showed a negative peak at ∼270 nm in the presence of excess Ag , implying that significant structural changes and a potential aggregation of DNA occurred. Subsequently, the Ag -mediated DNA strands are immobilized on Au surfaces. Their electrochemical properties are monitored using CV, EIS and SECM showing increased overpotentials and charge-transfer resistances, and decreased the rate constant in the presence of an excess of Ag , respectively. These results are further supported by the XPS and sulfide-Au reductive desorption measurements.
本文证明了 Ag 离子连续掺入含有相邻 C-C 错配的 dsDNA。与不含 Ag 的 DNA 相比，当加入三个 Ag 离子时，含有三个 C-C 错配的 DNA 的熔点（T ）升高了 8°C，而当存在过量 Ag 离子时，T 则无法获得，这表明在每个 C-C 错配掺入化学计量的 Ag 后，C-Ag-C 的稳定桥接。dsDNA 的圆二色性（CD）光谱在过量 Ag 的存在下在∼270nm 处显示出负峰，这意味着 DNA 发生了显著的结构变化和潜在的聚集。随后，Ag 介导的 DNA 链固定在 Au 表面上。使用 CV、EIS 和 SECM 监测它们的电化学性质，结果表明在过量 Ag 的存在下，过电势和电荷转移电阻增加，而速率常数降低。XPS 和硫化物-Au 还原解吸测量进一步支持了这些结果。
