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.