An integrated temporary negative pressure assisted microfluidic chip for DNA isolation and digital PCR detection

An integrated DNA purification and digital PCR (dPCR) detection microfluidic chip was developed in this study. This temporary negative pressure assisted microfluidic chip constructed of polydimethylsiloxane contained two distinct functional zones, one for DNA purification and the other for digital PCR (dPCR) detection. Sample lysate and reagent segments (washing buffer) for DNA purification were pre-loaded in a Teflon tube and pulled into the nucleic acids (NA) capture zone successively by negative pressure from the pipettor. The magnetic particles in the sample lysate were captured by the magnet and washed with buffer to get the purified DNA. DNA on magnetic particles were eluted by the PCR mix and then taken into the dPCR layer for dPCR reaction by the temporary negative pressure provided by the suction layer. Lastly, the suction layer was filled with water to avoid evaporation and ensure the efficiency of PCR in each chamber. This microdevice carried advantages such as ease of manufacture, ease of operation, and low cost.