A novel dicarboxyl-functionalized iron cryptate with a 2,2-pyridine unit has been synthesized, which displays outstanding electrochemical properties in water as a potential biosensing probe. Taking the silver ion (Ag⁺) as an example, we report a novel Ag⁺ assay by recording the electrochemical signals of Fe cryptate. In summary, a hairpin-structured DNA probe is designed and modified with the synthesized Fe cryptate. In the absence of Ag⁺, this is absorbed on the surface of a reduced graphene oxide modified electrode and a significant electrochemical response is obtained. In the presence of Ag⁺, cytosine–cytosine mismatches in the DNA probe recognize target ions and it is transformed into a conformation which cannot resist digestion by exonuclease III. As a result, Fe cryptate is released and Ag⁺ is recycled for continuous DNA digestion. By analyzing the reduced electrochemical signals of Fe cryptate, it is possible to quantify the target ions.

合成了具有2，2-吡啶单元的新型二羧基官能化铁矿酸盐，其在水中作为潜在的生物传感探针表现出出色的电化学性能。以银离子（Ag ⁺）为例，我们通过记录Fe隐酸盐的电化学信号报告了一种新颖的Ag ⁺测定。总而言之，设计了发夹结构的DNA探针，并用合成的Fe cryptate进行了修饰。在不存在Ag ⁺的情况下，其被吸附在还原的氧化石墨烯修饰电极的表面上，并获得了显着的电化学响应。在银⁺存在下，DNA探针中的胞嘧啶-胞嘧啶错配可识别靶标离子，并转化为无法抵抗核酸外切酶III消化的构象。结果，释放出铁的加密物，并回收了Ag ⁺以进行连续的DNA消化。通过分析还原的铁密酸盐的电化学信号，可以对目标离子进行定量。