纳米酶引起了广泛关注，合理设计高活性的纳米酶以提高其应用性能是一项长期目标。在此，以金属有机骨架衍生的具有大表面积和高孔隙度的Co3O4多面体作为纳米固载体，通过高温还原MnO4-离子和物理加载碳点（CDs），成功合成了Co3O4@MnO2@CDs多面体。通过癌细胞诱导的双抗体夹心策略，将Co3O4@MnO2@CDs多面体引入改性的TiO2纳米颗粒（NPs）电极，导致光电流的降低。Co3O4@MnO2@CDs多面体不仅可以熄灭TiO2 NPs的光电流，还可以作为纳米酶催化沉淀。此外，沉淀物不仅可以降低光电化学（PEC）响应，还可以增加Co3O4@MnO2@CDs多面体的熄灭能力。另外，Co3O4@MnO2@CDs-Ab偶联物的空间阻滞效应进一步削弱了光电流。基于多功能的Co3O4@MnO2@CDs多面体，提出了用于检测A549癌细胞的PEC生物传感器，其线性范围为102至106个细胞/毫升，检测极限为11个细胞/毫升。此外，该策略可以区分肺癌患者和健康个体。设计的多功能Co3O4@MnO2@CDs纳米酶为PEC癌细胞检测提供了新的视角，并具有在早期临床诊断和生物医学研究中的巨大潜力。版权所有 © 2023 Elsevier B.V. 保留所有权利。

Nanozymes have attracted widespread attention, and rationally designing high-activity nanozymes to improve their application performance are a long-term objective. Herein, taking metal-organic frameworks-derived Co3O4 polyhedron with large surface area and high porosity as nanoconfinement carriers, Co3O4@MnO2@CDs polyhedron was successfully synthesized by the room-temperature reduction of MnO4- ions and physical load of carbon dots (CDs). Through cancer cells-triggered double antibody sandwich strategy, the Co3O4@MnO2@CDs polyhedron were introduced to the TiO2 nanoparticle (NPs) modified electrode, leading to the decreased photocurrent. The Co3O4@MnO2@CDs polyhedron can not only quench the photocurrent of TiO2 NPs, also act as nanozymes to catalyze precipitates. Moreover, the precipitates can not only reduce the photoelectrochemical (PEC) response, also increase the quenching capacity of the Co3O4@MnO2@CDs polyhedron. Additionally, the steric hindrance effect of the Co3O4@MnO2@CDs-Ab conjugates further weaken the photocurrent. Based on the multifunctional Co3O4@MnO2@CDs polyhedron, the proposed PEC biosensor for the detection of A549 cancer cells exhibits a wide linear range from 102 to 106 cells/mL and a low detection limit of 11 cells/mL. Furthermore, this strategy can differentiate between lung cancer patients and healthy individuals. The designed multifunctional Co3O4@MnO2@CDs nanozymes provide a new horizon for PEC detection of cancer cells, and may have great potential in early clinical diagnosis and biomedical research.Copyright © 2023 Elsevier B.V. All rights reserved.