One-Pot Rlock-Mediated CRISPR/Cas12a-Driven RCA Cycle for Rapid and High-Sensitive APE1 Detection

Apurinic/apyrimidinic endonuclease 1 (APE1) is a key enzyme involved in DNA repair and cellular redox regulation, and is frequently overexpressed in tumor cells. This highlights the urgent need for a rapid and high-sensitive point-of-care testing (POCT) strategy for APE1 to facilitate early cancer diagnosis. Rolling circle amplification (RCA) is a widely used isothermal DNA amplification method; however, its application in APE1 detection remains rare. Here, we introduce a versatile RCA-Lock (Rlock) conversion platform that enables the transformation of RCA-based nucleic acid detection technologies into APE1-responsive assays. Building upon this platform, we further developed a novel POCT method for APE1 detection─Rlock-mediated, CRISPR/Cas12a-driven RCA cycle (RCRE)─which, for the first time, integrates CRISPR/Cas12a with RCA into a one-pot APE1 detection system. The RCRE assay achieves a limit of detection of 8.86 × 10–4 U/mL within 30 min, while requiring minimal equipment, low cost, and no complex handling procedures. This Rlock-based conversion strategy represents a transformative advance in the field of APE1 diagnostics and offers conceptual inspiration for the design of programmable nucleic acid–based biosensors. The resulting RCRE assay significantly broadens the technological landscape for early cancer detection and paves the way for future clinical translation.