Wei Xiaoqian, Song Shaojia, Song Weiyu, Xu Weiqing, Jiao Lei, Luo Xin, Wu Nannan, Yan Hongye, Wang Xiaosi, Gu Wenling, Zheng Lirong, Zhu Chengzhou
Key Laboratory of Pesticides and Chemical Biology of Ministry of Education, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China.
State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, P. R. China.
Anal Chem. 2021 Mar 30;93(12):5334-5342. doi: 10.1021/acs.analchem.1c00635. Epub 2021 Mar 18.
The rational construction of advanced sensing platforms to sensitively detect HO produced by living cells is one of the challenges in both physiological and pathological fields. Owing to the extraordinary catalytic performances and similar metal coordination to natural metalloenzymes, single atomic site catalysts (SASCs) with intrinsic peroxidase (POD)-like activity have shown great promise for HO detection. However, there still exists an obvious gap between them and natural enzymes because of the great challenge in rationally modulating the electronic and geometrical structures of central atoms. Note that the deliberate modulation of the metal-support interaction may give rise to the promising catalytic activity. In this work, an extremely sensitive electrochemical HO biosensor based on single atomic Fe sites coupled with carbon-encapsulated FeC crystals (FeC@C/Fe-N-C) is proposed. Compared with the conventional Fe SASCs (Fe-N-C), FeC@C/Fe-N-C exhibits superior POD-like activity and electrochemical HO sensing performance with a high sensitivity of 1225 μA/mM·cm, fast response within 2 s, and a low detection limit of 0.26 μM. Significantly, sensitive monitoring of HO released from living cells is also achieved. Moreover, the density functional theory calculations reveal that the incorporated FeC nanocrystals donate electrons to single atomic Fe sites, endowing them with improved activation ability of HO and further enhancing the overall activity. This work provides a new design of synergistically enhanced single atomic sites for electrochemical sensing applications.
构建先进的传感平台以灵敏检测活细胞产生的羟基自由基（HO）是生理和病理领域的挑战之一。由于具有非凡的催化性能以及与天然金属酶相似的金属配位，具有内在过氧化物酶（POD）样活性的单原子位点催化剂（SASC）在HO检测方面显示出巨大潜力。然而，由于在合理调控中心原子的电子和几何结构方面面临巨大挑战，它们与天然酶之间仍存在明显差距。需要注意的是，对金属-载体相互作用的刻意调控可能会产生有前景的催化活性。在这项工作中，提出了一种基于单原子铁位点与碳包覆的FeC晶体耦合的超灵敏电化学HO生物传感器（FeC@C/Fe-N-C）。与传统的铁单原子位点催化剂（Fe-N-C）相比，FeC@C/Fe-N-C表现出优异的POD样活性和电化学HO传感性能，灵敏度高达1225 μA/mM·cm，响应时间在2 s内，检测限低至0.26 μM。值得注意的是，还实现了对活细胞释放的HO的灵敏监测。此外，密度泛函理论计算表明，掺入的FeC纳米晶体向单原子铁位点提供电子，赋予它们更高的HO活化能力，进一步增强了整体活性。这项工作为电化学传感应用提供了一种协同增强单原子位点的新设计。
