The introduction of real time PCR (qPCR) revolutionized the world of molecular biology and provided scientists with a tool for obtaining truly quantitative nucleic acid data. While qPCR remains one of the most robust tools available on the bench, its resolution power is limited to changes in DNA concentration that are higher than 50%. This limitation is mainly due to the compounding of errors derived from each step in the quantification process. That’s where Droplet Digital PCR enters the picture.
Droplet Digital PCR alleviates the compounding error effect by partitioning samples into 20,000 droplets such that each copy of DNA is encapsulated in its own bubble. Subsequent amplification reactions are then carried out individually which leads to reduce background noise and therefore a more sensitive measurement of low concentrations of nucleic acid that may not have been detectable using qPCR.
Bio-Rad Laboratories‘ Frank Bizouarn recently published an outstanding article in Genetic Engineering and Biotechnology News detailing the benefits of ddPCR including a real life example. The article covers how ddPCR works and its use in gene-expression analysis, copy number variation determination and rare event detection.