(416f) Electrophoretic Separation of DNA By Normal Stress

Separating DNA by size is the basis of many biomedical analyses. With the rapid advancement of biotechnology, the demand for DNA separation technology is even stronger. In this study, we demonstrated the separation genomic DNA utilizing the phenomenon of DNA migration due to the normal stress. The migration happens when an elongated DNA moves along a curved streamline or an electric field line. The same as the Weissenberg effect, the normal stress make an elongated but curved DNA move towards its center of the curvature. Since the normal stress effect is more significant for longer DNA, it results in DNA separation by size. We have built a microfluidic device to demonstrate this principle. With the continuous injections of DNA, the sorting efficiency for T4-DNA reaches 0.57. With the batch injections, the sorting efficiency for T4-DNA further increases to 0.85, very close to a perfect separation (sorting efficiency =1). In comparison with the traditional electrophoresis, the normal stress causes DNA to separate in the direction perpendicular to DNA movement. Therefore, it is also possible to make DNA separate two-dimensionally by simultaneously applying both mechanisms.