Miao Peng, Han Kun, Wang Bidou, Luo Gangyin, Wang Peng, Chen Mingli, Tang Yuguo
1] CAS Key Lab of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, P. R. China [2] University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
CAS Key Lab of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, P. R. China.
Sci Rep. 2015 Mar 17;5:9161. doi: 10.1038/srep09161.
In this work, a novel strategy to fabricate a highly sensitive and selective biosensor for the detection of Ag(+) is proposed. Two DNA probes are designed and modified on a gold electrode surface by gold-sulfur chemistry and hybridization. In the presence of Ag(+), cytosine-Ag(+)-cytosine composite forms and facilitates the ligation event on the electrode surface, which can block the release of electrochemical signals labeled on one of the two DNA probes during denaturation process. Ag(+) can be sensitively detected with the detection limit of 0.1 nM, which is much lower than the toxicity level defined by U.S. Environmental Protection Agency. This biosensor can easily distinguish Ag(+) from other interfering ions and the performances in real water samples are also satisfactory. Moreover, the two DNA probes are designed to contain the recognition sequences of a nicking endonuclease, and the ligated DNA can thus be cleaved at the original site. Therefore, the electrode can be regenerated, which allows the biosensor to be reused for additional tests.
在这项工作中，提出了一种用于制造检测Ag(+)的高灵敏度和选择性生物传感器的新策略。通过金硫化学和杂交设计并在金电极表面修饰了两种DNA探针。在Ag(+)存在的情况下，形成胞嘧啶-Ag(+)-胞嘧啶复合物，并促进电极表面的连接事件，这可以阻止在变性过程中标记在两种DNA探针之一上的电化学信号的释放。可以以0.1 nM的检测限灵敏地检测Ag(+)，该检测限远低于美国环境保护局定义的毒性水平。这种生物传感器可以轻松地区分Ag(+)与其他干扰离子，并且在实际水样中的性能也令人满意。此外，两种DNA探针被设计为包含切口内切核酸酶的识别序列，因此连接的DNA可以在原始位点被切割。因此，电极可以再生，这使得生物传感器能够重复用于额外的测试。
