Nano-immunosorbent assay based on Cas12a/crRNA for ultra-sensitive protein detection

Apart from the great potential in genome editing, the clustered regularly interspaced short palindromic repeat (CRISPR)/Cas system has recently been widely used in biosensing. However, due to the complex and inefficient signal conversion strategies, most of the works focused on nucleic acid analysis rather than protein biomarkers. Herein, by employing DNA-AuNPs (gold nanoparticles) nanotechnology to activate trans-cleavage activity of CRISPR/Cas12a, a universal signal transduction strategy was established between trans-cleavage of CRISPR/Cas12a and protein analytes. As a result, a sensitive platform was developed for sensing carcinoembryonic antigen (CEA) and prostate specific-antigen (PSA) biomarkers, which was designated as Nano-CLISA (Nano-immunosorbent assay based on Cas12a/crRNA). Nano-CLISA was directly employed to test PSA in clinical samples, indicating its great potential in practical detection. This platform has been used to quantitatively analyze protein at attomolar levels, which was 1000-fold more sensitive than traditional ELISA, and the detection range is 15 times wider than that of traditional ELISA.