PNA-based light-up probes for real-time detection of sequence-specific PCR products

Area of Science:

• Molecular Biology
• Biotechnology
• Analytical Chemistry

Background:

• Real-time monitoring of Polymerase Chain Reaction (PCR) is crucial for quantitative DNA analysis.
• Existing methods may face limitations in sensitivity, specificity, or interference with amplification.
• Development of novel probes is needed for improved real-time PCR assays.

Purpose of the Study:

• To introduce and evaluate a peptide nucleic acid (PNA)-thiazole orange conjugate as a "light-up" probe for real-time PCR.
• To assess the probe's ability to monitor PCR product formation and quantify nucleic acids or intact cells.
• To determine the probe's performance characteristics, including linearity and detection limits.

Main Methods:

• A peptide nucleic acid (PNA) sequence-specific probe conjugated with thiazole orange was synthesized.
• The PNA-thiazole orange conjugate was employed as a "light-up" probe in real-time PCR.
• Hybridization of the probe to PCR amplicons resulted in an increased fluorescent signal.

Main Results:

• The PNA-thiazole orange conjugate demonstrated sequence-specific hybridization to PCR products, leading to a measurable increase in fluorescence.
• The "light-up" probe quantitatively measured DNA and intact bacterial cells without inhibiting PCR amplification.
• A linear detection range spanning at least 4 log units was achieved without system optimization.
• The detection limit for genomic *Yersinia enterocolitica* DNA was determined to be 0.4 pg per reaction mixture.

Conclusions:

• The peptide nucleic acid (PNA)-thiazole orange conjugate serves as an effective "light-up" probe for real-time PCR monitoring.
• This novel probe enables sensitive and quantitative detection of DNA and bacterial cells.
• The assay exhibits a broad linear dynamic range and a low detection limit, offering a valuable tool for molecular diagnostics.