A highly integrated digital PCR system with on-chip heating for accurate DNA quantitative analysis

Area of Science:

• Biotechnology
• Molecular Diagnostics
• Microfluidics

Background:

• Digital polymerase chain reaction (dPCR) enables highly sensitive disease diagnosis via single-molecule detection.
• Current dPCR systems face limitations including complex sample distribution, external heaters, and slow thermal cycling, hindering efficiency.

Purpose of the Study:

• To develop an improved dPCR system with an integrated self-heating chip for enhanced speed and efficiency.
• To optimize chip design for better sample partitioning and thermal uniformity.

Main Methods:

• Microwell array dPCR system with an integrated self-heating chip.
• Hydrodynamic and electrothermal simulations for chip optimization.
• Hydrophilic/hydrophobic surface modifications for sample compartmentalization.
• Indium tin oxide (ITO) heating layer and a custom temperature control algorithm for rapid, stable self-heating.

Main Results:

• Optimized chip design improved microwell partitioning and thermal distribution.
• The system demonstrated a dynamic linear range of 10^5 and a detection limit of 10 copies/reaction for EGFR plasmid DNA.
• Quantitative detection of BCR-ABL1 mutation gene fragments showed comparable analytical accuracy to a commercial dPCR system.

Conclusions:

• The developed self-heating dPCR system significantly enhances efficiency and speed.
• Cost-effective chip manufacturing via semiconductor lines promotes widespread adoption and accessibility.
• This integrated dPCR platform offers a promising solution for sensitive and efficient molecular diagnostics.