COF-confined CsPbBr3 nanocomposite with CRISPR/Cas12a-driven DNA walking for ultrasensitive electrochemiluminescent detection of circulating tumor DNA.

A highly sensitive electrochemiluminescence biosensor was developed for circulating tumor DNA detection by integrating a covalent organic framework-confined CsPbBr3 nanocomposite with a CRISPR/Cas12a-driven amplification strategy. The covalent organic framework not only stabilizes CsPbBr3 nanocrystals in aqueous environments but also regulates interfacial charge transfer and enables programmable immobilization of DNA probes. Upon recognition of the target sequence, Cas12a is activated and progressively cleaves surface-tethered quencher-modified DNA strands, leading to stepwise restoration of electrochemiluminescence emission. This surface-confined signal amplification eliminates the need for polymerase chain reaction or isothermal preamplification. Under optimized conditions, the biosensor exhibited a linear response over a concentration range from 10 fM to 10 nM, with a detection limit of 5.4 fM. The method demonstrated good selectivity toward single-base mismatches and satisfactory performance in diluted serum and clinical plasma samples. These results highlight a synergistic material-enzyme strategy for sensitive and robust nucleic acid detection and provide a proof-of-concept platform for electrochemiluminescence-based circulating tumor DNA analysis.