Ratiometric Sensing for Ultratrace Tetracycline Using Electrochemically Active Metal–Organic Frameworks as Response Signals
Nini Liang, Xuetao Hu, Xinai Zhang, Wenting Li, Ziang Guo, Xiaowei Huang, Zhihua Li, Roujia Zhang, Tingting Shen, Xiaobo Zou, Jiyong Shi
Abstract
A novel ratiometric sensor using an electrochemically active metal–organic framework of Mo@MOF-808 and NH 2 -UiO-66 as response signals was developed to detect tetracycline (TET) in ultratrace quantities. To achieve the dual-response strategy, Mo@MOF-808, with a reduction peak at −1.06 V, and NH 2 -UiO-66, with an oxidation peak at 0.724 V, were used as signal probes directly. Concretely, Mo@MOF-808, single-stranded DNA (ssDNA), and complex system (Apt@NH 2 -UiO-66) of aptamer (Apt) and NH 2 -UiO-66 were sequentially immobilized on the electrode. With the addition of TET, Apt was hybridized with TET and Apt@NH 2 -UiO-66 was detached from the electrode, resulting in an increase in the current at −1.06 V and a decrease in the current at 0.724 V. Through this strategy, the sensor achieved a wide linear range (0.1–10000 nM) and a low limit of detection (0.009792 nM) for TET. Moreover, the ratiometric sensor exhibited better sensitivity, reproducibility, and stability than a single-signal sensor. Furthermore, the constructed sensor was successfully applied to detect TET in milk samples, suggesting excellent application prospects.