Wu Yao, Lai Rebecca Y
Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA.
Biotechnol J. 2016 Jun;11(6):788-96. doi: 10.1002/biot.201500428. Epub 2016 Mar 15.
Ag(I) is known to interact with cytosine (C) via the formation C-Ag(I)-C complexes. The authors have utilized this concept to design six electrochemical Ag(I) sensors using C-rich DNA probes. Alternating current voltammetry and cyclic voltammetry were used to analyze the sensors. The results show that the dual-probe sensors that require the use of both 5'- and 3'-thiolated DNA probes are not suitable for this application, the differences in probe orientation impedes formation of C-Ag(I)-C complexes. Sensors fabricated with DNA probes containing both thymine (T) and C, independent of the location of the alkanethiol linker, do not response to Ag(I) either; T-T mismatches destabilize the duplex even in the presence of Ag(I). However, sensors fabricated with DNA probes containing both adenine (A) and C are ideal for this application, owing to the formation of C-Ag(I)-C complexes, as well as other lesser known interactions between A and Ag(I). Both sensors are sensitive, specific and selective enough to be used in 50% human saliva. They can also be used to detect silver sulfadiazine, a commonly prescribed antimicrobial drug. With further optimization, this sensing strategy may offer a promising approach for detection of Ag(I) in environmental and clinical samples.
已知银离子（Ag(I)）通过形成C-Ag(I)-C复合物与胞嘧啶（C）相互作用。作者利用这一概念，使用富含C的DNA探针设计了六种电化学Ag(I)传感器。采用交流伏安法和循环伏安法对传感器进行分析。结果表明，需要同时使用5'-和3'-硫醇化DNA探针的双探针传感器不适用于此应用，探针方向的差异阻碍了C-Ag(I)-C复合物的形成。用同时含有胸腺嘧啶（T）和C的DNA探针制备的传感器，无论烷硫醇连接体的位置如何，对Ag(I)也无响应；即使在有Ag(I)存在的情况下，T-T错配也会使双链体不稳定。然而，用同时含有腺嘌呤（A）和C的DNA探针制备的传感器非常适合此应用，这是由于形成了C-Ag(I)-C复合物，以及A与Ag(I)之间其他鲜为人知的相互作用。这两种传感器都足够灵敏、特异且具有选择性，可用于50%的人类唾液中。它们还可用于检测磺胺嘧啶银，一种常用的抗菌药物。通过进一步优化，这种传感策略可能为检测环境和临床样本中的Ag(I)提供一种有前景的方法。
