Using a special protein and Cas12a to detect tetracycline with high sensitivity

The detection range for tetracycline can be tuned from 6.0-100 nM to 20-600 nM by adjusting the TetR-to-template ratio.

• A hierarchical cascade signal amplification platform integrates rolling circle transcription with CRISPR-Cas12a for detecting antibiotic residues.
• In the absence of tetracycline, a molecular switch blocks transcription; upon tetracycline addition, transcription is triggered, producing crRNA copies.
• The system generates amplified signals through Cas12a-mediated cleavage of fluorescent reporters.
• Detection limits are identified at 1.35 nM and 16.4 nM for different ranges.
• The platform shows excellent selectivity against common interferents and achieves recoveries between 90% and 110% in spiked aquaculture tailwater.

Simplified