Nanofluidic trap for DNA extraction from biological samples

A new device seamlessly integrating various electrokinetic processes enables the analysis of short ssDNA (20 bases) directly from whole blood. An electrokinetic trap was integrated to achieve extraction, concentration, and desalting of ssDNA in 200 s followed by a 90 s electrophoretic separation. The trap consists of two sequentially coupled nanojunctions with different pore size and exhibits selective ion transport properties. Depletion forces near the nanojunctions and the apparent electromigration were tuned to enable the trapping and subsequent analysis of fluorescein labeled-ssDNA. The quantitation limit (S/N ratio = 10) was 12.5 nM using 40 μL of spiked whole blood.