A Programmable DNA Nanomachine‐Integrated Sensing Platform for Ultrasensitive, Serum‐Compatible Electrochemiluminescence Detection of Protein Biomarkers

ABSTRACT The development of robust and ultrasensitive biosensing technologies is crucial for advancing life science research and point‐of‐care diagnostics. Here, we report an integrated electrochemiluminescence (ECL) sensing platform that achieves exceptional sensitivity by incorporating a programmable DNA nanomachine as a signal amplification module with an efficient nanoparticle‐based ECL resonance energy transfer (RET) pair. The platform features a luminol‐functionalized Au/ZIF‐67 nanocomposite as a catalytic emitter and Ag@CuS nanospheres as quenchers. Target recognition triggers the autonomous walking of an Exonuclease III‐powered DNA nanomachine on the electrode surface, driving the cyclic assembly of quenchers and resulting in pronounced ECL quenching via RET. This engineered technology demonstrates ultrasensitive detection of the model protein, brain‐derived neurotrophic factor (BDNF), with a limit of detection of 9.0 fg mL −1 , a wide linear range over six orders of magnitude, and excellent accuracy in human serum. The platform exhibits high reproducibility and stability, underscoring its potential as a versatile and reliable technological foundation for next‐generation diagnostic devices.