Yu Peikai, Chen Lichuan, Zhang Yanxi, Zhao Shiqiang, Chen Zhixin, Hu Yong, Liu Junyang, Yang Yang, Shi Jia, Yao Zhiyi, Hong Wenjing
State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, 361005 Xiamen, China.
College of Food Science and Nutritional Engineering, China Agricultural University, 100083 Beijing, China.
Anal Chem. 2022 Sep 6;94(35):12042-12050. doi: 10.1021/acs.analchem.2c01592. Epub 2022 Aug 15.
The tunneling current through the single-molecule junctions principally offers the ultimate solution for chemical and biochemical sensing via the interactions between probes and target analytes at the single-molecule level. However, it remains unexplored to achieve the sensitive and selective detection of targeted analytes using single-molecule junction techniques due to the challenge in quantitative evaluation of sensing sensitivity and selectivity. Herein, we demonstrate a single-molecule tunneling sensor for the highly sensitive and selective detection of nitrobenzene explosives using scanning tunneling microscope break junction (STM-BJ). Taking advantage of π-π stacking interactions between the molecular probes and nitrobenzene explosives, we use a spectral clustering algorithm to assign the signal of probes and π-stacked probes for sensitively detecting the targeted analytes and the distinguishable conductance change of probes when interacting with different nitroaromatic explosive compounds for selective detection. We find that pronounced conductance changes up to 0.8 orders of magnitude when the probes interact with TNT. Also, we obtain a sensitivity of up to ∼10 pM for TNT and high sensitivity for eight TNT analogues. Combined with theoretical calculations, we discover that the harness of the destructive quantum interference of the probe M1OH after interacting with TNT leads to high selectivity in sensing with TNT. Our work demonstrates the great potential of the single-molecule tunneling current for environmental sensing molecules with high selectivity and sensitivity.
通过单分子结的隧穿电流主要为在单分子水平上通过探针与目标分析物之间的相互作用进行化学和生化传感提供了最终解决方案。然而，由于在传感灵敏度和选择性的定量评估方面存在挑战，利用单分子结技术实现对目标分析物的灵敏和选择性检测仍未得到探索。在此，我们展示了一种利用扫描隧道显微镜断结（STM-BJ）对硝基苯炸药进行高灵敏和选择性检测的单分子隧穿传感器。利用分子探针与硝基苯炸药之间的π-π堆积相互作用，我们使用光谱聚类算法来区分探针和π堆积探针的信号，以灵敏地检测目标分析物，并利用探针与不同硝基芳香族炸药化合物相互作用时可区分的电导变化进行选择性检测。我们发现，当探针与TNT相互作用时，电导变化高达0.8个数量级。此外，我们对TNT的灵敏度高达约10 pM，对八种TNT类似物也具有高灵敏度。结合理论计算，我们发现探针M1OH与TNT相互作用后利用其破坏性量子干涉可实现对TNT传感的高选择性。我们的工作证明了单分子隧穿电流在对环境传感分子进行高选择性和高灵敏度检测方面的巨大潜力。
