CRISPR/Cas12a-coupled organic electrochemical transistors for highly sensitive detection of methylated DNA.

Abstract

DNA methylation is an important epigenetic biomarker for early disease screening and prognosis evaluation, but its reliable detection remains challenging because methylated DNA is often present at low abundance in complex biological backgrounds. Here, we report a methylation-sensitive bioelectronic sensing platform that integrates AciI-assisted target discrimination, CRISPR/Cas12a-mediated trans-cleavage, and vertical organic electrochemical transistors (vOECTs) amplification for highly sensitive methylated DNA detection. In this strategy, unmethylated DNA is selectively digested by AciI, while intact methylated DNA activates the crRNA-guided Cas12a system, triggering collateral cleavage of ssDNA reporters immobilized on the Au gate electrode. The resulting interfacial changes are efficiently amplified by the vOECTs through coupled electric-double-layer gating. The platform achieved quantitative methylated DNA detection from 100 fM to 100 pM with a sensitivity of 267.6 μA/dec and a detection limit of 100 fM. The sensor also exhibited good operational stability, reproducibility, and reliable recovery performance in artificial serum samples. This work demonstrates the potential of CRISPR/vOECTs bioelectronics for sensitive epigenetic analysis and presents a promising proof-of-concept for future non-invasive screening strategies.