Digital PCR and Microfluidics: How dPCR Works

What is digital PCR?

Unlike traditional real-time PCR (qPCR), which reads a single bulk fluorescence curve, digital PCR partitions the reaction mix into thousands of tiny compartments — each holding zero, one, or a few target molecules. After amplification, every partition is simply scored positive or negative, and Poisson statistics convert the positive fraction into an absolute molecule count, with no standard curve required.

The role of microfluidics

Microfluidics creates the partitions. There are two main formats: droplet digital PCR (ddPCR), which uses droplet microfluidics to make thousands of uniform water-in-oil droplets, and chip- or array-based dPCR, which uses microfabricated chambers or through-hole arrays. Either way, uniform partition size is critical for an accurate count.

Why choose dPCR over qPCR?

• Absolute quantification — no standard curve needed.
• Precision — resolves small differences and low-abundance targets.
• Inhibitor tolerance — partitioning dilutes the effect of inhibitors.
• Sensitivity — detects rare targets, ideal for liquid biopsy and low viral loads.

Applications

dPCR is used in oncology liquid biopsy (detecting rare mutant alleles), infectious-disease viral-load testing, copy-number variation, GMO and contamination testing, and quantifying NGS libraries.

Designing dPCR chips

Accurate dPCR needs uniform partitioning, clean surfaces and low-autofluorescence materials such as COC or COP. Production scales through injection moulding — see prototype to scale.

Frequently asked questions