Complete Prevention of Bubbles in a PDMS-Based Digital PCR Chip with a Multifunction Cavity.

Area of Science:

• Biotechnology
• Materials Science
• Microfluidics

Background:

• Bubble generation in polydimethylsiloxane (PDMS)-based digital PCR (dPCR) chips at high temperatures is a significant challenge.
• High saturated vapor pressure of water at elevated temperatures is identified as the primary cause of bubble formation.
• Existing dPCR systems face limitations due to bubble-related issues, impacting performance and reliability.

Purpose of the Study:

• To investigate and mitigate bubble formation in PDMS-based dPCR chips.
• To develop a novel dPCR chip design that ensures bubble-free operation.
• To enhance the efficiency and simplicity of digital PCR processes.

Main Methods:

• Systematically analyzed the causes of bubble generation in PDMS dPCR chips.
• Implemented a pressure reduction strategy to below 13.6 kPa to counteract water vapor pressure.
• Designed and fabricated a chip with an integrated cavity coated with Parylene C.
• Utilized the cavity for degassing and water storage during the PCR process.

Main Results:

• Bubble formation was effectively prevented by controlling system pressure and chip design.
• Achieved bubble-free operation in the dPCR chip.
• Demonstrated fast digitization, valve-free operation, and eliminated the need for tubing connections.
• The Parylene C coating and cavity design proved effective for various functions including degassing and thermal management.

Conclusions:

• Reducing system pressure and incorporating a specialized cavity are effective strategies to prevent bubble formation in dPCR chips.
• The novel chip design offers a robust solution for bubble-free digital PCR.
• The developed dPCR system provides a simplified, efficient, and high-performance platform for molecular diagnostics.