Figure 3.

(A) A depletion front generated by the ion-exchange membrane G extends to the junction between the two cross-channels, the bottom vertical channel and the horizontal channel. Spiked DNA serum flows from the bottom vertical channel to the right of the horizontal channel before exiting by another vertical channel, as shown by the blue line. The high field in the junction extracts the DNA and places it in a buffer to the left of the horizontal channel. (B) Spiked microRNA and DNA into serum is tested with the pretreatment chip. The reverse-transcription PCR yield of microRNA is shown to be more than 4 times higher than the best commercial pretreatment unit. There is no PCR amplification of the DNA without pretreatment (Reproduced from [10] with permission from the Royal Society of Chemistry).