A Sensitive and Nonoptical CRISPR Detection Mechanism by Sizing Double-Stranded λ DNA Reporter

Area of Science:

• Molecular Biology
• Biotechnology
• Biosensor Technology

Background:

• CRISPR-based biosensors typically use costly reporters and equipment.
• Existing methods include colorimetric, fluorescent, and electrochemical signaling.

Purpose of the Study:

• To develop a simple, inexpensive, non-optical CRISPR-Cas12a biosensor.
• To detect single-stranded DNA (ssDNA) targets using a novel reporting mechanism.

Main Methods:

• Utilized CRISPR-Cas12a system with double-stranded lambda DNA as a reporter molecule.
• Quantified lambda DNA size reduction via gel electrophoresis.
• Investigated Cas12a trans-nuclease activity and binding affinity with lambda DNA.

Main Results:

• Demonstrated a sensitive CRISPR-Cas12a platform for ssDNA detection.
• Achieved sub-picomolar detection sensitivity, approximately 100 times more sensitive than fluorescent methods.
• Hypothesized Cas12a's activity is due to looped structures in lambda DNA and strong binding affinity.

Conclusions:

• The physical size change of lambda DNA offers a novel reporting mechanism for CRISPR biosensors.
• This approach enables the use of various double-stranded DNA molecules as CRISPR reporters.
• The developed platform provides a cost-effective and sensitive alternative for nucleic acid detection.