Liu Menghan, Zhang Ruyu, Wang Jie, Zhang Huiting, Tan Jingying, Liu Qingzhi, Han Lei, Lu Lihua
College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, Shandong 266109, China.
Key Laboratory of Tobacco Pest Monitoring Controlling & Integrated Management, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, Shandong 266101, China.
Anal Chem. 2025 Jul 1;97(25):13404-13413. doi: 10.1021/acs.analchem.5c01779. Epub 2025 Jun 17.
Bimetallic nanozymes not only have strong synergistic catalysis ability but also may improve the catalytic specificity of the nanozymes. Herein, the oxidase (OXD)-mimic Ir/Co bimetallic nanozymes were prepared through a coordination reaction between the Ir(III) complex with the 2-methylimidazole (MeIm) ligands in ZIF-67 under mild conditions without the pyrolysis and physical doping procedures. It is found that the trace amount of Ir-modified ZIF-67 (Ir@ZIF-67) possesses 18.17-fold that of catalytic ability and 7.86-fold that of the reaction rate as those of pristine ZIF-67. On the other hand, compared with ZIF-67, the OXD-like specificity of Ir@ZIF-67 has been increased 9.7%. The theoretical simulation shows that the high-performance of Ir@ZIF-67 comes from its higher O adsorption ability. In virtue of the high performing OXD-like catalytic property, Ir/Co bimetallic nanozymes are employed to establish a simple and sensitive colorimetric pesticides detection platform without deleterious HO, which offers excellent "switch-on" malathion (MAL) detection in the linear range of 0.05-25 μM with a limit of detection (LOD) of 11.8 nM. Moreover, Ir/Co bimetallic nanozymes are successfully fabricated into the MAL test swabs. Assisted by a color-reading APP, the test swabs can detect MAL with the LOD as low as 18.5 nM. Surprisingly, such a simple test swab can achieve such high sensitivity for MAL detection. The real sample analysis verifies the high potential of the test swabs in practical application. The excellent performance of the fabricated test swabs can promote the formation of the situation where pesticides detection can be tested at any time and any place and can be carried out by anyone. This work not only provides a novel approach to designing polymetallic nanozymes but also displays the promising application of Ir/Co bimetallic nanozymes in the field of colorimetric sensing.
双金属纳米酶不仅具有强大的协同催化能力，还可能提高纳米酶的催化特异性。在此，通过在温和条件下，使Ir(III)配合物与ZIF-67中的2-甲基咪唑（MeIm）配体发生配位反应，制备了具有氧化酶（OXD）模拟活性的Ir/Co双金属纳米酶，无需热解和物理掺杂过程。研究发现，痕量Ir修饰的ZIF-67（Ir@ZIF-67）的催化能力是原始ZIF-67的18.17倍，反应速率是原始ZIF-67的7.86倍。另一方面，与ZIF-67相比，Ir@ZIF-67的类氧化酶特异性提高了9.7%。理论模拟表明，Ir@ZIF-67的高性能源于其更高的O吸附能力。凭借其高性能的类氧化酶催化特性，Ir/Co双金属纳米酶被用于建立一个简单灵敏的比色法农药检测平台，该平台无需有害的HO，在0.05 - 25 μM的线性范围内对马拉硫磷（MAL）进行出色的“开启”检测，检测限（LOD）为11.8 nM。此外，Ir/Co双金属纳米酶成功制备成MAL测试拭子。在颜色读取APP的辅助下，测试拭子对MAL的检测限低至18.5 nM。令人惊讶的是，如此简单的测试拭子对MAL检测能达到如此高的灵敏度。实际样品分析验证了测试拭子在实际应用中的高潜力。所制备测试拭子的优异性能可促进形成随时随地可由任何人进行农药检测的局面。这项工作不仅为设计多金属纳米酶提供了一种新方法，还展示了Ir/Co双金属纳米酶在比色传感领域的广阔应用前景。
