Fluorescence origami paper-based analytical device based on strand displacement assay for SARS-CoV-2 cDNA detection

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Molecular Diagnostics

Background:

• Point-of-care testing (POCT) requires rapid, sensitive, and portable diagnostic tools.
• DNA detection is crucial for diagnosing infectious diseases, including COVID-19.
• Existing methods can be time-consuming and require specialized laboratory equipment.

Purpose of the Study:

• To develop a fluorescence origami paper-based analytical device (Flu-oPAD) for DNA detection.
• To create a POCT sensing platform for sensitive and selective DNA analysis.
• To demonstrate the applicability of Flu-oPAD for detecting SARS-CoV-2 DNA.

Main Methods:

• Utilized a strand displacement assay with a fluorescence-quenched probe system.
• Integrated sample loading, incubation, and washing steps onto a single paper device.
• Developed a multi-array Flu-oPAD for simultaneous detection of multiple viral gene targets.

Main Results:

• Achieved a DNA detection linearity range from 0.1 nM to 10 μM with a 0.1 nM detection limit.
• Demonstrated high selectivity for target DNA, completing assays within 15 minutes.
• Successfully detected SARS-CoV-2 complementary DNA (cDNA) in nasopharyngeal swab samples, showing agreement with RT-PCR.

Conclusions:

• The developed Flu-oPAD is a promising POCT tool for DNA screening.
• The device offers simplicity, portability, cost-effectiveness, and accessibility for healthcare.
• Flu-oPAD has significant potential for rapid diagnostics of infectious diseases like COVID-19.