Rapid detection of Staphylococcus aureus using a CRISPR/Cas14a-assisted electrochemical aptasensor and PCN-222@AuPt nanozyme-induced amplification strategy

The rapid determination of Staphylococcus aureus ( S.auerus ) is essential for advancing food safety monitoring and control. In this study, we developed a novel electrochemical aptasensor leveraging the trans-cleavage activity of CRISPR/Cas14a, augmented by nanomaterial modification and nanozyme-catalyzed signal amplification, to enable ultrasensitive and selective detection of S. aureus . The glassy carbon electrode (GCE) was modified with chromium-based metal–organic framework/polypyrrole/gold nanoparticle composites (Cr-MOF/PPy@Au), significantly improving electrical conductivity and biocompatibility. The aptamer-mediated specific recognition of S. aureus was coupled with CRISPR/Cas14a trans-cleavage activity, ensuring high detection specificity. Simultaneously, the peroxidase (POD)-like catalytic activity of the zirconium-porphyrin metal-organic framework hybridized with AuPt nanoparticles (PCN-222@AuPt nanozyme) facilitated the efficient conversion of hydrogen peroxide into hydroxyl radicals , thereby amplifying the electrochemical signal. Under optimized experimental parameters, the proposed sensor achieved a broad linear detection range from 5 × 10 ¹ to 5 × 10⁷ CFU mL⁻¹ and a low detection limit of 10 CFU mL⁻¹ . This study work presents a reproducible and highly selective platform for S. aureus detection, highlighting its potential for future applications in food safety monitoring. • An ultrasensitive electrochemical biosensor was presented for S.auerus detection. • CRISPR/Cas14a and PCN-222@AuPt nanozyme were first integrated into a sensing system. • PCN-222@AuPt nanozyme had the excellent peroxidase-like activity. • The electrochemical biosensor showed good feasibility in milk samples.