CRISPR/Cas12a dual-mode biosensor for Staphylococcus aureus detection via enzyme-free isothermal amplification

Accurate and reliable detection of Staphylococcus aureus (S. aureus) is essential for preventing infections, particularly in healthcare and food safety contexts. This work presents a novel dual-mode biosensor that integrates the CRISPR/Cas12a system with an enzyme-free isothermal amplification method for detecting S. aureus. Hybridization chain reaction (HCR) and catalytic hairpin assembly (CHA) amplify the aptamer-triggered response, significantly enhancing sensitivity. CRISPR/Cas12a's nuclease activity is utilized in two modes: cis cleavage generates a fluorescence signal, while trans cleavage produces an electrochemical signal, enabling dual-mode detection. The biosensor demonstrates outstanding performance, with a limit of detection (LOD) as low as 5.7 CFU mL^-1 in electrochemical mode and 133.7 CFU mL^-1 in fluorescence mode, showcasing excellent accuracy, stability, and sensitivity. It has been successfully applied to detecting actual samples, confirming its practical applicability. This innovative approach offers a powerful tool for the swift and precise identification of S. aureus and paves the way for developing next-generation dual-mode biosensors for various analytes. Future research will aim to simplify the detection process further, making it more accessible for use in resource-limited settings.