Faradaic-free electrokinetic nucleic acid amplification (E-NAAMP) using localized on-chip high frequency Joule...

Area of Science:

• Biotechnology
• Molecular Biology
• Electrochemistry

Background:

• Conventional Joule heating methods for nucleic acid amplification (NAA) face challenges with electrode-generated electrolysis by-products.
• Existing methods require electrode isolation and gas venting, complicating microscale applications.

Purpose of the Study:

• To introduce a novel Faradaic reaction-free nucleic acid amplification (NAA) method for microscale liquid samples.
• To overcome limitations of previous Joule heating techniques by eliminating electrolysis by-products.

Main Methods:

• Utilized a radio frequency (RF) alternating current electric field with microscale thin film gold electrodes.
• Applied a high-frequency RF potential (10-40 MHz) to induce Ohmic current and Joule heating directly within the nucleic acid reaction mixture.
• Demonstrated thermal regulation for loop-mediated isothermal amplification and polymerase chain reaction.

Main Results:

• Achieved sustainable Joule heating for several hours without pH change or observable gaseous electrolysis by-products.
• Successfully performed direct thermal amplification using loop-mediated isothermal amplification and polymerase chain reaction.
• Demonstrated sustained operation (>50 h) with minimal enzyme activity loss and no electrode delamination.

Conclusions:

• The electrokinetic Nucleic Acid Amplification (E-NAAMP) method enables miniaturized NAA systems by providing efficient, reaction-free thermal regulation.
• This RF Joule heating approach offers a simplified and robust alternative for microfluidic and portable NAA devices.