A Continuous-Flow Polymerase Chain Reaction Microchip With Regional Velocity Control

Area of Science:

• Biotechnology
• Microfluidics
• Molecular Biology

Background:

• Continuous-flow polymerase chain reaction (PCR) enables rapid DNA amplification.
• Microfluidic devices offer miniaturization and precise control over reaction conditions.
• Optimizing DNA sample velocity in microchannels is crucial for efficient thermal cycling.

Purpose of the Study:

• To present a continuous-flow PCR microchip with a serpentine microchannel of varying width for regional velocity control.
• To optimize DNA sample exposure times to different temperature phases.
• To minimize transitional periods during temperature changes in PCR.

Main Methods:

• Finite element analysis (FEA) and semi-analytical heat transfer modeling were used to design heating assemblies.
• Infrared (IR) thermography was employed for temperature validation.
• Micro particle image velocimetry (mu-PIV) and flow-field FEA were used to analyze fluid dynamics.

Main Results:

• The microchip design allowed for controlled DNA sample velocities by varying channel width.
• FEA and experimental data showed good agreement for thermal and flow fields.
• Successful amplification of a Bacillus anthracis DNA fragment was demonstrated.

Conclusions:

• Regional velocity control in a continuous-flow PCR microchip is achievable through variable channel geometry.
• This approach enhances the efficiency of thermal cycling and DNA amplification.
• The developed microchip is a promising platform for rapid molecular diagnostics.