CRISPR-Programmable Nanoparticle Transport in Salt-Gated Porous Media for Visual DNA Detection

Area of Science:

• Biomaterials Science
• Nanotechnology
• Molecular Diagnostics

Background:

• Paper-based diagnostics often rely on passive capillary action for nanoparticle transport.
• Controlling nanoparticle behavior in porous media is crucial for developing advanced diagnostic tools.

Purpose of the Study:

• To engineer CRISPR-programmable nanoparticles with actively regulated transport in paper-based diagnostic systems.
• To establish a salt-activated adhesion mechanism for controlling nanoparticle movement.
• To develop a distance-based visual readout for DNA detection.

Main Methods:

• Functionalizing gold nanoparticles with hydrophobic DNA for salt-activated adhesion to cellulose fibers.
• Utilizing CRISPR-Cas12a system for target-specific DNA probe cleavage.
• Coupling salt-gated transport with Cas12a activity for Herpes simplex virus 1 (HSV-1) DNA detection.
• Employing optical and electron microscopy to analyze nanoparticle-fiber interactions.

Main Results:

• Demonstrated that hydrophobic DNA-functionalized nanoparticles adhere to cellulose fibers at high ionic strength, while others migrate freely.
• Developed a semi-quantitative, distance-based visual readout based on nanoparticle front length.
• Achieved naked-eye detection of HSV-1 DNA with a limit of detection of 100 aM in 45-60 minutes.
• Clinical sample evaluation showed 96.2% sensitivity and 100% specificity compared to qPCR.

Conclusions:

• Established a general strategy for programming nanoparticle transport in porous media via surface chemistry.
• Validated a novel salt-gated transport system for sensitive and specific DNA detection in paper-based diagnostics.
• Showcased the potential of this approach for rapid, point-of-care diagnostic applications.