Split G-quadruplex-programmed label-free CRISPR-Cas12a sensing system.

A split G-quadruplex (G4)-programmed Cas12a platform was established, validated, and optimized. The split G4 motif was recruited as substrate for Cas12a, and the label-free sensing platform provided a concentration-dependent response towards the input target. Furthermore, exosomal surface proteins from cultured cancer cells and clinical samples were detected and profiled.