An integrated pH "Pen" for visual nucleic acid detection based on colorimetrical LAMP at point-of-care testing

Area of Science:

• Biotechnology
• Molecular Diagnostics
• Point-of-Care Testing

Background:

• Nucleic acid detection is vital for infectious disease control.
• Current methods often require complex equipment, limiting point-of-care applications.
• A simple, portable, and visual detection device is needed for remote areas.

Purpose of the Study:

• To develop an integrated, portable device for visual nucleic acid detection.
• To utilize pH changes during loop-mediated isothermal amplification (LAMP) for endpoint detection.
• To enable nucleic acid detection in resource-limited settings.

Main Methods:

• Developed a pH "Pen" device integrating a pH test strip with a portable metal block for isothermal amplification.
• Employed a non-buffered LAMP system and a sealed chamber to prevent interference with the pH test strip.
• Utilized an image analysis method (G/R value) for objective colorimetric result interpretation.

Main Results:

• The pH "Pen" successfully amplified and detected the OTU2m gene within 28 minutes.
• Achieved a limit of detection of 2.0 × 10^2 copies/mL, comparable to real-time fluorescence methods.
• Demonstrated simplicity, affordability, and portability for visual nucleic acid analysis.

Conclusions:

• The integrated pH "Pen" offers a promising solution for nucleic acid detection at the point-of-care.
• The device is suitable for settings with limited access to advanced laboratory infrastructure.
• This method provides a simple, visual, and sensitive approach to molecular diagnostics.