Electrochemical Impedimetric Real-Time Polymerase Chain Reactions Using Anomalous Charge Transfer Enhancement

Area of Science:

• Electrochemistry
• Molecular Biology
• Biosensing

Background:

• Polymerase chain reaction (PCR) is a fundamental technique in molecular biology for DNA amplification.
• Real-time monitoring of PCR is crucial for accurate quantification and efficiency assessment.
• Existing real-time PCR methods often rely on complex optical detection systems.

Purpose of the Study:

• To develop a new electrochemical impedimetric method for real-time PCR detection.
• To investigate the use of a specific DNA intercalator, [Ru(bpy)2DPPZ]2+, for monitoring PCR.
• To establish a cost-effective and portable alternative to optical PCR detection.

Main Methods:

• Utilized electrochemical impedance spectroscopy (EIS) to monitor changes in charge transfer resistance (Rct).
• Employed the DNA intercalator [Ru(bpy)2DPPZ]2+ and redox mediators K4[Fe(CN)6]/K3[Fe(CN)6] with a carbon electrode.
• Performed EIS measurements during each elongation heat cycle of the PCR process.

Main Results:

• The DNA intercalator [Ru(bpy)2DPPZ]2+ anomalously enhanced charge transfer, initially resulting in low Rct.
• As PCR progressed, amplicon dsDNA increased, leading to a steep rise in Rct due to intercalated [Ru(bpy)2DPPZ]2+.
• The increase in Rct per heat cycle (ΔRct) correlated with template DNA amount and peaked at the same cycle as optical detection.

Conclusions:

• Electrochemical impedimetric monitoring provides accurate real-time detection of PCR amplification.
• The developed method offers a simple, cost-effective, and potentially portable solution for PCR analysis.
• This approach opens avenues for developing new generations of accessible molecular diagnostic tools.