A rapid and ultrasensitive CRISPR-Cas12a assay for clinical detection of pathogens and mutations.

CRISPR-Cas12a-driven nucleic acid diagnostics offer considerable potential for highly specific and rapid detection. However, their practical applications are limited by the necessity for pre-amplification of target DNA to enhance sensitivity. To overcome this limitation, we developed Auto-catalyst, a novel one-pot, amplification-free DNA detection platform employing a two-stage autocatalytic Cas12a cascade. This approach integrates a positive feedback amplification mediated by a circular crRNA-DNA nanostructure with an asymmetric CRISPR reaction driven by split crRNA. Without external amplification, this system detects DNA fragments at concentrations as low as 80 aM within 30 min at room temperature and maintains high specificity, accurately distinguishing single-base mutations down to 1 fM. Clinical validation demonstrated successful detection of pathogenic DNA in cerebrospinal fluid samples from patients with intracranial infections, highlighting its potential for rapid bedside diagnostics essential for timely clinical decision-making. Additionally, Auto-catalyst accurately identified the clinically significant isocitrate dehydrogenase 1 (IDH1) gene R132H mutation from glioma tissue samples. This integrated two-stage autocatalytic Cas12a strategy represents a powerful, convenient, and promising diagnostic tool suitable for point-of-care applications.