Target-to-signal conversion and spatial enrichment cascade boost CRISPR/Cas12a biosensing for trace-level pathogen...

Area of Science:

• Biotechnology
• Biosensor Technology
• Molecular Diagnostics

Background:

• Salmonella Typhimurium (S. typhimurium) is a major cause of foodborne illness, necessitating rapid detection methods.
• Current detection strategies often lack the required speed, sensitivity, or accuracy for effective food safety monitoring.
• Developing advanced biosensors is crucial for identifying S. typhimurium in contaminated food sources.

Purpose of the Study:

• To develop a novel CRISPR/Cas12a-activated DNA nanowire biosensor for sensitive S. typhimurium detection.
• To leverage DNAzyme catalysis and HCR amplification for enhanced signal generation.
• To create a rapid, accurate, and user-friendly detection platform for foodborne pathogens.

Main Methods:

• Construction of a DNA nanowire biosensor incorporating DNAzyme-catalyzed amplification and HCR signal enrichment.
• Utilized CRISPR/Cas12a system for specific cleavage of DNA nanowires, leading to fluorescence signal restoration.
• Optimized reaction conditions to achieve high sensitivity and a wide linear detection range.

Main Results:

• The developed biosensor demonstrated ultra-sensitive detection of S. typhimurium.
• Achieved a linear detection range from 10^1 to 10^5 cfu mL^-1.
• Established a limit of detection (LOD) as low as 6.26 cfu mL^-1.
• The method showed straightforward operation, rapid response, and high sensitivity.

Conclusions:

• The CRISPR/Cas12a-activated DNA nanowire biosensor provides a highly sensitive and rapid method for S. typhimurium detection.
• This platform offers significant advantages for food safety applications and pathogen surveillance.
• Potential for adaptation to detect other foodborne pathogens by modifying recognition elements.