An AuPt nanozyme-assisted CRISPR/Cas12a system for visual nucleic acid detection of pathogens.

Potato early blight, caused by Alternaria solani, presents a significant threat to the potato industry. Existing detection methods for A. solani often fail to simultaneously achieve simplicity and accuracy. A gold-platinum (AuPt) nanozyme-assisted CRISPR/Cas12a system, termed the nanoparticle enzyme-assisted CRISPR detection (NACD assay) was developed. By integrating the precise target recognition of CRISPR with the enzyme-like activity of AuPt nanozymes, this system achieves simple, sensitive, and visual detection of A. solani. The NACD assay provided visual results through a distinct color change produced by the substrate catalyzed by the AuPt nanozyme. It can detect 100 copies/μL of the target dsDNA (A. solani 5.8S rRNA gene) and 10⁻3 ng/μL A. solani genomic DNA. This detection method demonstrates high specificity, with no cross-reactivity observed with three other pathogens. Moreover, the incorporation of a filter paper-based readout enables straightforward visual detection by the naked eye, making it particularly suitable for on-site testing. Overall, these features make it an effective on-site diagnostic tool, allowing the potato industry to manage early diseases more efficiently.