The new absolute in PCR – Digital PCR

The power of digital PCR – finding a needle in a haystack

Digital PCR (dPCR) is a technique where the sample is partitioned into many individual reactions so that either zero, one or more target molecules are present in each reaction. This approach makes it surprisingly easy to detect a single positive against a strong background of negatives, a typical needle in a haystack problem. It is in such instances that the lower limit of detection excludes standard real-time quantitative PCR (qPCR) as a viable method.

The defining feature of digital PCR is the absolute quantification of nucleic acids. After partitioning, the reactions undergo end-point PCR cycling, and partitions are analyzed for the presence (positive reaction) or absence (negative reaction) of a fluorescent signal. Based on this information, one can calculate the absolute number of molecules present in the sample. Unlike qPCR, dPCR does not rely on standard curves. Thanks to this, dPCR has a lower detection limit and higher precision than qPCR.

Researchers increasingly use digital PCR for sensitive applications, such as copy number variation analysis, gene expression quantification and rare target detection. The method has helped advance cell and gene therapy research, cancer research, infectious disease surveillance, food testing, and many more.

Unveiling the magic inside

Sample partitioning methods in digital PCR include microfluidic chips, microarrays, spinning microfluidic discs, and droplet techniques based on oil-water emulsions. Reimagining familiarity, ease of use and finer resolution, we have developed microfluidic nanoplates to achieve superior partitioning and enhanced digital PCR data.

No droplets. No crystals. No chips.

The key advantages of performing digital PCR in nanoplates include but are not limited to:

• User-friendly, familiar plates are easy to pipet just like for qPCR
• Fixed partitions prevent variation in size and coalescence
• Sealed nanoplates prevent well to well contamination
• Faster readout possible due to simultaneous reading of all partitions of a sample
• Integrated quality control, meaning one can look at the plate image for single fluorescent signals from the individual positive partition counts
• Plates are amenable to front-end automation

Advantages over droplet digital PCR (ddPCR)

Besides the advantages highlighted above, the nanoplate-based QIAcuity Digital PCR System offers significant benefits over droplet digital PCR-based systems.

The entire digital PCR workflow is integrated into one system, making it substantially faster with less hands-on time and higher scalability.

Read more about dpcr vs ddpcr