SELF-ASSEMBLED MAGNETIC COLLOIDS FOR DNA SEPARATIONS IN MICROFLUIDIC DEVICES

摘要

We present a new approach to separations in microchannels, using superparamagnetic colloids as a self-organizing matrix. In a magnetic field, the colloidal suspension forms a 2-dimensional array of columns with +m-sized spacing. This rigid matrix reverts back to a low viscosity suspension when the field ceases, allowing easy replacement between runs. It is applied here to constant and pulsed-field electrophoresis of large duplex DNA molecules in an automated microfluidic system. Fragments ranging from 15-145.5 kilobase pairs were separated in about 10 mn. Single molecule epifluorescence microscopy was used to unravel the mechanisms responsible for these separations.