An RNA-Guided Cas9 Nickase-Based Method for Universal Isothermal DNA Amplification

Area of Science:

• Molecular Biology
• Biotechnology
• Genetics

Background:

• Accurate and sensitive nucleic acid detection is crucial for various biological and medical applications.
• Existing amplification methods often require thermal cycling, limiting their field applicability.
• There is a need for rapid, isothermal amplification techniques with high specificity.

Purpose of the Study:

• To develop a novel isothermal DNA amplification method using Cas9 nickase.
• To evaluate the sensitivity, specificity, and speed of the new method.
• To demonstrate the potential of Cas9nAR for routine nucleic acid detection.

Main Methods:

• Cas9 nickase-based amplification reaction (Cas9nAR) was developed.
• The method utilizes a sgRNA:Cas9n complex, a strand-displacing DNA polymerase, and specifically designed primers.
• DNA amplification occurs through cycles of priming, extension, nicking, and displacement at a constant 37°C.

Main Results:

• Cas9nAR achieved a zeptomolar limit of detection (2 copies in 20 μL) within 60 minutes.
• The method demonstrated single-base discrimination capability.
• Cas9nAR showed simplicity in primer design and broad applicability.

Conclusions:

• Cas9nAR is a highly sensitive and specific isothermal DNA amplification method.
• The technique is rapid, simple to implement, and suitable for quantitative nucleic acid detection.
• Cas9nAR has significant potential for both basic research and applied diagnostic studies.