Electromagnetically controlled microfluidic chip for DNA extraction

A microfluidic chip for DNA extraction by using solid phase extraction method was demonstrated in this paper. The microfluidic chip features three PDMS layers with microchannels, and a silica bead well with a thin PCTE membrane sandwiched between two PDMS layers. The height difference between the microchannels in the top PDMS layer and the bottom PDMS layer generates a gravity-based pressure difference to transport the regent and washing buffer solutions. Since the DNA extraction process based on solid phase extraction involves multiple sequential steps (i.e., loading, washing, and elution), an automated electromagnetically controlled valve-array was designed and used to control the flow sequence of the required reagents and washing buffer. It was demonstrated that by using this chip and HindIII-digested k-phage DNA as the sample, the DNA extraction process can be completed within 15 min and the DNA extraction efficiency is approximately 50%. Such a simple and automatic microfluidic chip system eliminates many complicated hardware and human intervention, and can perform the DNA extraction with relatively high efficiency. (C) 2015 Elsevier Ltd. All rights reserved.