酶生物燃料电池已成为生物传感的强有力工具，然而通常因生物酶的有限装载效率、低催化活性和稳定性差而受到限制。本文使用鞣酸（TA）进行结构刻蚀合成了分层多孔金属有机框架（MOF），实现葡萄糖脱氢酶（GDH）和烟酰胺腺嘌呤二核苷酸（NAD+）辅因子在沸石咪唑醇框架（ZIF-L）中的共同包埋，并进一步用作生物催化微反应器来修改生物阳极。在本研究中，TA控制的刻蚀不仅可以扩大微反应器的孔径，还可以使酶在低表面能量形态下重新定向，因此增强了辅因子依赖型酶的生物催化作用。同时，在微反应器上组装了拓扑DNA四面体，作为微RNA响应式“锁”，在生物阳极上执行外切酶III辅助目标回收的级联信号放大和在生物阴极上执行杂交链反应（HCR）。所提出的自供电生物传感器已实现了低至2 aM（5 µL样品中6个miRNA-21拷贝）的检测限度，进一步成功应用于基于miRNA-21不同水平识别癌细胞和乳腺癌患者的临床血清，具有在准确疾病诊断和临床诊断中具有巨大潜力。© 2023 Wiley-VCH GmbH。

Enzymatic biofuel cells have become powerful tools in biosensing, which however generally suffer from the limited loading efficiency as well as low catalytic activity and poor stability of bioenzymes. Herein, the hierarchical porous metal-organic frameworks (MOFs) are synthesized using tannic acid (TA) for structural etching, which realizes co-encapsulation of glucose dehydrogenase (GDH) and nicotinamide adenine dinucleotide (NAD+ ) cofactor in zeolitic imidazolate framework (ZIF-L) and are further used as the biocatalytic microreactors to modify bioanode. In this work, the TA-controlled etching can not only expand the pore size of microreactors, but also achieve the reorientation of enzymes in their lower surface energy form, therefore enhancing the biocatalysis of cofactor-dependent enzyme. Meanwhile, the topological DNA tetrahedron is assembled on the microreactors, which acts as the microRNA-responsive "lock" to perform the cascade signal amplification of exonuclease III-assisted target recycling on bioanode and hybridization chain reaction (HCR) on biocathode. The proposed self-powered biosensor has achieved a detection limit as low as 2 aM (6 copies miRNA-21 in a 5 µL of sample), which is further successfully applied to identify cancer cells and clinical serums of breast cancer patients based on the different levels of miRNA-21, holding great potential in accurate disease identification and clinical diagnosis.© 2023 Wiley-VCH GmbH.