Engineered tracrRNA for enabling versatile CRISPR-dCas9-based biosensing concepts.

Area of Science:

• Biotechnology
• Molecular Biology
• Biosensing

Background:

• CRISPR-Cas technologies are gaining traction in biosensing due to their sequence specificity for nucleic acid detection.
• Current CRISPR-Cas9 systems for biosensing often rely on complex protein engineering or lack efficient signal amplification.
• Dead Cas9 (dCas9) systems are explored but typically require intricate protein modifications and struggle with signal amplification.

Purpose of the Study:

• To develop a straightforward method for integrating flexible signal generation and amplification into CRISPR-dCas9 complexes.
• To demonstrate novel nucleic acid engineering approaches for enhanced CRISPR-based biosensing.
• To overcome limitations of existing dCas9 biosensing strategies regarding signal amplification and complexity.

Main Methods:

• Engineered a CRISPR-dCas9 complex by incorporating a DNA sequence into the trans-activating CRISPR RNA (tracrRNA).
• Utilized the incorporated DNA for two signal generation modes: DNAzyme activity or as a hybridization site for labeled probes.
• Demonstrated signal generation in solution and on solid surfaces, including magnetic microbeads.

Main Results:

• Successfully integrated flexible signal generation and amplification into a CRISPR-dCas9 complex without complex protein engineering.
• Demonstrated two distinct amplified fluorescent signal generation strategies using the engineered tracrRNA.
• Validated the approach in a proof-of-concept assay for detecting single-stranded DNA on magnetic microbeads.

Conclusions:

• The novel CRISPR-dCas9 engineering approach enables flexible and amplified signal generation for biosensing.
• This method simplifies the development of CRISPR-based biosensors compared to existing dCas9 strategies.
• The engineered system shows significant promise for diverse CRISPR-based nucleic acid detection applications.