Isothermal Amplification Using Temperature-Controlled Frequency Mixing Magnetic Detection-Based Portable...

Area of Science:

• Biotechnology
• Biosensing
• Molecular Diagnostics

Background:

• Sensitive magnetic nucleic acid (NA) detection using frequency mixing magnetic detection (FMMD) requires precise temperature control for amplified NA samples.
• Recombinase polymerase amplification (RPA) is a crucial step for NA amplification but necessitates stable temperature conditions.

Purpose of the Study:

• To investigate the feasibility of integrating RPA with a mobile FMMD setup for temperature-controlled NA amplification.
• To develop and validate thermal models for accurate temperature control within the FMMD sensor unit under varying ambient conditions.

Main Methods:

• Utilized the inherent heat generated by the low-frequency (LF) excitation signal of FMMD, controlled via pulse width modulation (PWM).
• Developed steady-state and dynamic response models to predict thermal behavior at the sample position.
• Validated RPA performance within the FMMD sensor unit against a standard temperature-controlled water bath.

Main Results:

• Demonstrated successful temperature control for RPA within the FMMD sensor unit, achieving performance comparable to a water bath.
• Developed accurate thermal models: linear extrapolation for narrow temperature ranges and a lumped parameter model (LPM) for broader conditions.
• Confirmed the effectiveness of PWM for controlling temperature using the LF excitation signal's heat.

Conclusions:

• The integrated FMMD system with PWM-based temperature control enables reliable RPA for nucleic acid amplification.
• The developed thermal models accurately predict sample temperature, facilitating operation in diverse point-of-care (PoC) environments.
• This approach holds promise for nucleic acid amplification and magnetic detection using FMMD in resource-limited settings.