A glucose/O2 biofuel cell as self-powered sensor for ultrasensitive microRNA detection based on CRISPR-Cas12a cleavage and duplex-specific nuclease-assisted target recycling

The development of effective strategies for the construction of enzymatic biofuel cell based self-powered biosensors is important. Herein, we report ultrasensitive self-powered sensing of microRNA by integrating a glucose/O2 biofuel cell with CRISPR-Cas12a-based cleavage and duplex-specific nuclease (DSN) assisted target recycling. For the construction of the bioanode, glucose oxidase (GOD) is immobilized on Au nanoparticles-graphene nanosheets nanocomposite modified electrode by using a short single-stranded DNA as a bridge. The target miRNA-155 can initiate DSN-assisted target recycling and CRISPR-Cas12a cleavage toward ssDNA, leading to the release of GOD from the bioanode. Because of the decreased loading capacity of GOD on the bioanode at increasing miRNA-155 concentration, the short-circuit current of the glucose/O2 biofuel cell decreases, enabling self-powered sensing of miRNA-155. The self-powered biosensor features a wide dynamic range for detecting miRNA-155 from 10−16 to 10−10 M, with an ultralow detection limit of 23 aM. This work provides a highly sensitive self-powered biosensing platform for miRNA detection.