DNA cube-gated ratiometric ECL/SERS biosensor for APE1 via HCR-driven interfacial reconstruction

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Nanotechnology

Background:

• Apurinic/apyrimidinic endonuclease 1 (APE1) is crucial in DNA repair pathways.
• Sensitive and reliable detection of APE1 activity is vital for understanding DNA repair and disease.
• Existing biosensing methods often lack sensitivity, selectivity, or stability.

Purpose of the Study:

• To develop a dual-mode ratiometric biosensor combining electrochemiluminescence (ECL) and surface-enhanced Raman scattering (SERS) for sensitive APE1 activity monitoring.
• To engineer a novel nanocomposite transducer for integrated signal generation and amplification.
• To establish a causality-locked amplification-capture strategy for self-referenced quantification.

Main Methods:

• Fabrication of a hierarchical Ti3C2/CsPbBr3@PDA@Au nanocomposite transducer.
• Assembly of a wireframe DNA cube with a hairpin capture module for signal amplification and capture.
• Utilizing hybridization chain reaction (HCR) for signal amplification upon APE1 cleavage.
• Implementing a ratiometric readout (ISERS/IECL) for self-referenced quantification.

Main Results:

• The dual-mode biosensor demonstrated sensitive detection of APE1 activity over a wide range (1×10⁻⁸–1×10⁻² U/mL).
• An anti-correlated output (ECL-off, SERS-on) was observed, enabling ratiometric quantification.
• The sensor showed excellent selectivity, repeatability, stability, and fabrication reproducibility.
• Ratiometric readout improved tolerance to baseline drift and electrode variability.

Conclusions:

• A novel dual-mode ratiometric ECL/SERS biosensor was successfully developed for APE1 activity monitoring.
• The integrated nanocomposite transducer and DNA-based amplification-capture strategy offer a robust platform for biosensing.
• This work provides a valuable design concept for ratiometric biosensing in complex biological matrices.