Figure 7.

A continuous-flow PCR device where microfluidic droplets move through a temperature gradient toward the radial direction. The device contains an oil inlet (A) that joins an aqueous inlet channels (B) to form droplets (C). The droplets pass through the inner circles in the hot zone (D) to ensure initial denaturation of the template and travel on to the periphery where primer annealing and template extension occur (E). The droplets then flow back to the centre, where the DNA is denatured and a new cycle begins. For illustration, only 7 cycles are demonstrated, but 34 cycles have been achieved in [116].