MICROFABRICATED SIEVE FOR THE CONTINUOUS SORTING OF MACROMOLECULES

In a two-dimensional periodic but asymmetric environment, a Brownian p article that is driven in one direction by a potential gradient will a lso drift in the orthogonal direction at a rate that depends an its di ffusion coefficient. On this basis, we propose a new method for separa ting biological macromolecules according to size. A fine stream of mol ecules is electrophoresed through a microfabricated sieve, etched from a silicon chip by lithography. The sieve consists of a periodic array of oblong obstacles, which deflect the molecules so that each species follows a different trajectory, oblique to the flow. Advantages promi sed by the technique include improved efficiency, continuous sorting a nd ready automation.