Decoding DNA labels by melting curve analysis using real-time PCR

Area of Science:

• Biotechnology
• Molecular Biology
• Analytical Chemistry

Background:

• Synthetic DNA is utilized for object authentication, but current methods rely on complex DNA sequencing or length variation analysis.
• Existing DNA-based authentication protocols face limitations in terms of cost, speed, and complexity for widespread industrial adoption.

Purpose of the Study:

• To develop a simplified, cost-effective, and rapid DNA-based authentication protocol for object labeling.
• To create a high-complexity DNA barcode system using a limited set of synthetic DNA sequences with varying melting points.

Main Methods:

• Designing a DNA coding system with 8 template groups, each containing 4 distinct DNA templates, to generate over 2.5 billion unique melting temperature (Tm) and ID code combinations.
• Utilizing quantitative PCR (qPCR) for a two-step code amplification and decoding process based on differential DNA melting points.
• Validating the protocol's reproducibility and specificity using a complex mixture of 32 DNA products across 8 Tm-defined groups.

Main Results:

• Successfully generated a DNA barcode system capable of >2.5 billion unique combinations based on melting temperature (Tm) and ID codes.
• Demonstrated high reproducibility and specificity in decoding complex DNA mixtures with 32 distinct products.
• Successfully labeled a drone with a DNA code embedded in oil-based paint, proving industrial applicability and successful decoding.

Conclusions:

• The presented method offers a simple, robust, and scalable DNA authentication system using synthetic DNA sequences with distinct melting points.
• The cost-effective and rapid qPCR-based decoding protocol makes this method suitable for a wide array of authentication and anti-counterfeiting applications.
• This innovative approach provides a powerful tool for securing physical objects and products against unauthorized replication or tampering.