Silicon microstructure arrays for DNA extraction by solid phase sample contacting at high flow rates

Rapid and large sample volume processing capabilities are required for many clinical and environmental point of care genetic diagnostics scenarios. In this paper we describe the development of a silicon monolithic device for high flow rate DNA extraction. The silicon presents silica surfaces and with chaotropic salt solutions can be used for solid phase extraction. The microfluidic device was designed with the aid of simulation methods and consists of a chamber containing a densely packed alternating array of teardrop-shaped microstructures. The microstructures repeatedly separate and recombine flows, and produce a near homogeneous flow distribution to favour DNA contact with the large silica surface areas. Extremely high flow rate operation (e.g. 10 mL min−1) can be achieved without device failure. Low DNA loading and elution flow rates were used to determine a binding capacity of 57 ± 5 ng cm−2. At high flow rates the DNA extraction capability is retained and is independent of the sample DNA concentration. High flow rate operation is preferred for the rapid extraction of rare DNA species from large sample volumes, and makes the device ideal for inclusion within a fully integrated genetic diagnostics system.