Colorimetric Nucleic Acid Detection on Paper Microchip Using Loop Mediated Isothermal Amplification and Crystal...

Area of Science:

• Biotechnology
• Analytical Chemistry
• Biosensing

Background:

• Nucleic acid detection is critical for food safety and infectious disease diagnostics.
• Existing methods often require complex instrumentation and are costly.
• There is a need for rapid, cost-effective, and label-free nucleic acid detection techniques.

Purpose of the Study:

• To develop a paper microchip-based colorimetric assay for nucleic acid detection and quantification.
• To create a rapid, cost-effective, and label-free method with minimal instrumentation.
• To demonstrate the assay's utility for detecting DNA from food samples and microbial pathogens.

Main Methods:

• DNA extraction from food samples and microbial pathogens.
• Loop-mediated isothermal amplification (LAMP) for DNA amplification.
• Detection and quantification of LAMP amplicons on a wax-patterned paper microchip using crystal violet dye for colorimetric sensing.

Main Results:

• The crystal violet dye showed affinity for double-stranded DNA (dsDNA), indicated by a color change from colorless to purple.
• Successful detection and quantification of Sus scrofa (porcine) DNA down to 1 pg/μL.
• Successful detection and quantification of Bacillus subtilis (bacteria) DNA down to 10 pg/μL.

Conclusions:

• The developed paper microchip assay provides a simple, inexpensive, and rapid method for nucleic acid detection.
• This colorimetric sensing approach is adaptable for various DNA samples, including those relevant to food safety and diagnostics.
• The technology holds potential for developing point-of-need diagnostic tools.