A self-digitization chip integrated with hydration layer for low-cost and robust digital PCR

Area of Science:

• Biotechnology
• Molecular Diagnostics
• Microfluidics

Background:

• Quantitative nucleic acid detection is crucial for molecular diagnostics.
• Existing digital PCR (dPCR) platforms can be costly and complex.
• Evaporation loss during thermal cycling affects assay accuracy.

Purpose of the Study:

• To develop a low-cost, robust microfluidic digital PCR (dPCR) device.
• To achieve zero-water-loss during dPCR thermal cycling.
• To enable sensitive and accurate absolute quantification of nucleic acids.

Main Methods:

• Integration of a vacuum accumulator and hydration reservoir using polydimethylsiloxane (PDMS) film.
• Design of a microfluidic chip with 10,000 picoliter reaction chambers.
• Utilizing PDMS permeability for vacuum energy storage and evaporation compensation.

Main Results:

• The device achieved reliable single-DNA-molecule amplification and detection.
• Zero-water-loss was confirmed across all reaction chambers during thermal cycling.
• Accurate absolute quantification of T790M DNA (10-10^4 copies/μL) with a 10^4 dynamic range was demonstrated.

Conclusions:

• The developed self-discretization dPCR chip offers a simple, robust, and cost-effective solution for quantitative nucleic acid assays.
• The zero-water-loss feature enhances assay reliability and accuracy.
• The device is suitable for low-cost molecular diagnostics in resource-limited settings.