TdT/Cas12a cascade amplification biosensor for sensitive ALP activity detection

This study presents a novel biosensor based on TdT and CRISPR-Cas12a, which integrates the catalytic activity of terminal deoxynucleotidyl transferase (TdT) with the <i>trans</i>-cleavage property of CRISPR-Cas12a to achieve ultra-sensitive biomolecular detection. The biosensor exhibited a broad linear detection range from 0 to 0.2 U L^-1 and a remarkably low detection limit of 1.7 × 10^-3 U L^-1, demonstrating high specificity and sensitivity. In practical validation, the biosensor successfully quantified alkaline phosphatase (ALP) activity in both cervical cancer cells and HeLa cell lysates, even at a dilution factor of up to 10⁶-fold. Its sensitivity allowed precise detection at the single-cell level. This technology offers a robust, simple, and cost-effective platform for cancer diagnosis, treatment monitoring, and enzyme inhibitor screening, while maintaining excellent detection performance in complex biological samples. This breakthrough establishes a foundation for serological tumor screening and early disease diagnosis, while also opening new avenues for enhanced cancer management and clinical translation, indicating significant potential in translational medicine.