Cube-track encoded dual-mode ECL/SERS biosensor for ultrasensitive NF-κB p50 detection via transcription-DSN cascade.

Accurate quantification of trace transcription factors remains challenging because protein-nucleic acid recognition must be translated into a robust signal while resisting matrix interference and instrumental drift. Here, we report a dual-mode ratiometric biosensor for ultrasensitive detection of NF-κB p50 by integrating a CsPbBr3@PDA@AuNPs/MXene (PAM) hybrid transducer with a programmable nucleic-acid cascade and a wireframe DNA cube-track interface. In this design, NF-κB p50 initiates a DNA regulatory circuit that generates amplified nucleic-acid outputs through T7 transcription, which subsequently drive DSN-assisted cleavage of ferrocene (Fc) tags positioned on cube tracks at the electrode surface. This target-programmed interfacial Fc depletion simultaneously restores the PAM electrochemiluminescence (ECL-on) and attenuates the Fc Raman signal (SERS-off), enabling a self-calibrated ratiometric readout. The biosensor exhibits a wide working range from 0.1 to 1000 pM and an estimated limit of detection of 2.3 × 10-3 pM based on the 3σ criterion, further supported by additional low-concentration experimental verification. Selectivity studies against closely related NF-κB family proteins and high-concentration non-specific proteins confirm strong target/non-target discrimination, while repeatability, electrode-to-electrode reproducibility, stability assays, and spike-recovery experiments in diluted MCF-7 cell lysate demonstrate reliable operation in complex samples. This work establishes a general protein-to-nucleic-acid information conversion strategy coupled with cube-track encoded dual-mode transduction, providing a practical route for sensitive and robust transcription-factor analysis and offering potential for further miniaturization and point-of-care applications.