A sticky end-driven PAM-free RPA-CRISPR/Cas12a dual amplification system for ultrasensitive detection of KRAS G12C

Herein, a fluorescent biosensing platform was constructed for KRAS G12C single base mutation detection by CRISPR/Cas12a-coupled RPA without the PAM site. The KRAS G12C gene sequence was cleaved into double-stranded DNA containing a sticky end using HindIII enzyme cleavage site specificity. Sticky end dsDNA activated the <i>trans</i>-cleavage activity of Cas12a and generates an intense fluorescent signal. This strategy detected KRAS G12C targets in a linear range of 10 aM-10 pM with a detection limit of 1.5 aM. What's more, the method was able to distinguish 0.1% KRAS G12C mutation in a total of 10 pM gene concentration and demonstrated excellent detection performance in real samples.