MARPLE: A Proximity-Triggered CRISPR-Cas13 Platform for Ultrasensitive Antibody Detection

Area of Science:

• Biotechnology
• Molecular Diagnostics
• CRISPR Technology

Background:

• Antibody monitoring is crucial for disease diagnosis and therapeutic response assessment.
• Traditional immunoassays (e.g., ELISA) have limitations in workflow complexity and point-of-care application.
• CRISPR-Cas13, effective for nucleic acids, has potential for protein biomarker detection.

Purpose of the Study:

• To develop a novel CRISPR-Cas13-based platform for ultrasensitive antibody detection.
• To demonstrate the versatility and performance of the platform across various antibody targets.
• To establish a new tool for immunodiagnostics beyond nucleic acid sensing.

Main Methods:

• Introduction of MARPLE (Modular Antibody Recognition via Proximity-triggered Linker Exchange), a CRISPR-Cas13 platform.
• Utilizing antibody-induced proximity to trigger a strand displacement reaction and release an RNA target.
• Activation of Cas13 for collateral cleavage of fluorescent RNA reporters.

Main Results:

• Achieved ultrasensitive antibody detection at femtomolar concentrations.
• Demonstrated MARPLE's versatility with diverse targets (anti-digoxigenin, anti-cholesterol, anti-HA, trastuzumab, anti-MUC1).
• Showcased applications in infectious disease, cancer diagnostics, and therapeutic drug monitoring.
• Confirmed robust performance in complex matrices like human serum (isothermal, one-pot assay).

Conclusions:

• MARPLE is a versatile and ultrasensitive platform for antibody detection.
• The platform extends CRISPR-based diagnostics to protein biomarkers.
• MARPLE shows significant promise for immunodiagnostics, including point-of-care applications.