Closed-Loop Microreactor on PCB for Ultra-Fast DNA Amplification: Design and Thermal Validation

Area of Science:

• Biotechnology
• Microfluidics
• Molecular Diagnostics

Background:

• Polymerase Chain Reaction (PCR) is essential for DNA amplification in medical diagnostics.
• Microfluidic PCR (μPCR) reactors offer advantages for pathogen detection.
• Closed-loop (CL) μPCR designs improve upon traditional continuous-flow systems by using circular microchannels.

Purpose of the Study:

• To computationally evaluate three distinct CL μPCR designs for printed circuit board (PCB) fabrication.
• To fabricate and experimentally validate the most efficient CL μPCR design on a PCB substrate.
• To assess the computational model's accuracy by comparing simulated and experimental thermal performance.

Main Methods:

• A 3D heat transfer model was employed to simulate temperature distribution and calculate residence times in CL μPCR designs.
• The optimal CL μPCR design was fabricated on a PCB, integrating microheaters.
• Thermal performance was experimentally validated using a thermal camera, comparing measured temperatures and power consumption with computational predictions.

Main Results:

• Computational analysis indicated that the best CL μPCR design could achieve 30 PCR cycles in under 3 minutes.
• Experimental validation confirmed the computational model's accuracy, with measured temperatures closely matching simulated values.
• Measured power consumption was 1.521 W, showing a minimal ~7.3% deviation from the calculated 1.417 W.

Conclusions:

• The developed CL μPCR chip fabricated on PCB represents a significant advancement in rapid DNA amplification technology.
• The validated computational model accurately predicts the thermal performance of PCB-based CL μPCR devices.
• This low-cost, reproducible, and mass-amenable fabrication method holds great promise for future point-of-care diagnostics.