Droplet Libraries for Digital PCR with Improved Dynamic Range

Kaminski, Tomasz S. ;   Postek, Witold ;   Debski, Pawel R. ;   Garstecki, Piotr

This paper reports a microfluidic system that i) generate a sequence of 20 microliter droplets of a 2-fold dilution of DNA concentration ii) split each of the parental drops with flow-focusing module into c.a. thousand of tightly monodisperse daughter drops iii) allow for off-chip deposition of libraries in a tube for a PCR iv) re-inject the emulsion to a detection module for read-out of a fluorescence signal and v) enable for precise quantification of the DNA load. The system allows for precise determination of DNA concentration in a broad dynamic range, using the number of partitions reduced by the orders of magnitude in comparison to classical digital assays.