A TdT-driven amplification loop increases CRISPR-Cas12a DNA detection levels

Area of Science:

• Molecular Biology
• Biotechnology
• Nucleic Acid Chemistry

Background:

• CRISPR-Cas systems offer innovative pathogen detection but often require DNA pre-amplification, limiting point-of-care applications.
• Enhancing CRISPR-Cas assay sensitivity without pre-amplification is a significant challenge for rapid diagnostics.

Purpose of the Study:

• To introduce a Terminal deoxynucleotidyl Transferase (TdT)-based amplification strategy for CRISPR-Cas12a systems.
• To improve the sensitivity of CRISPR-Cas12a pathogen detection assays without the need for DNA pre-amplification.

Main Methods:

• Developed a positive feedback loop using TdT and a novel oligonucleotide enhancer (POISER) within a CRISPR-Cas12a assay.
• Cas12a-mediated trans-cleavage of FRET reporters and POISER initiates TdT-dependent elongation, creating new targets for amplified Cas12a activation.
• Utilized fluorescent-based detection to monitor signal amplification in the TdT-enhanced CRISPR-Cas12a system.

Main Results:

• The POISER-cycles significantly enhanced signal strength in fluorescent CRISPR-Cas12a assays.
• Demonstrated successful amplification of detection signals without requiring prior DNA amplification steps.
• Showcased the potential for increased sensitivity in pathogen detection using this novel method.

Conclusions:

• The TdT-based POISER amplification loop offers a promising strategy to boost CRISPR-Cas12a assay sensitivity.
• This method holds potential for advancing point-of-care diagnostics, disease surveillance, and environmental monitoring.
• Further optimization of the POISER system could lead to more robust and widely applicable CRISPR-based detection tools.