A suction-type, pneumatic microfluidic device for rapid DNA extraction

This current study presents a new miniature, integrated system capable of rapid extraction of genomic DNA (gDNA) from saliva samples. Three major components of the DNA extraction chip, including six symmetrical, normally-closed microvalves, a sample transport/mixing unit and a waste unit are integrated in this device. The microfluidic DNA extraction chip was made of CNC machining and PDMS casting processes to integrate a liquid channel layer, an air chamber layer and a glass layer on a single chip. Liquid samples can be transported and mixed by the suction-type sample transport/mixing unit by using micropumps, micromixers and normally-closed microvalves. Experimental results showed the pumping rate can be as high as 400 μL/min at an applied pressure of -70 KPa for an air chamber with a depth of 1.5 mm. A mixing efficiency as high as 96.5% can be achieved within 3 sec. Experimental data also showed that gDNA with an average concentration of 45 ± 3 ng/μL and an optical intensity (OD) value (260/280) of 1.5 ± 0.2 from ten measurements can be successfully achieved within 25 minutes. Consequently, the proposed miniature system can provide a powerful platform for automatic, rapid DNA extraction.