High performance sieving of biomolecules in a capillary-well motif

We report a novel artificial sieve featuring a periodic array of 70-nm capillaries interleaved with deep wells: the capillary-well motif. Integration of cylindrical capillaries and subsequent scaling of their diameter are achieved by standard fabrication techniques and surface tension driven shape transformation of a doped glass layer on silicon. High resolution rapid sieving of DNA and proteins within broad size ranges is presented in continuous-flow as well as batch separation modes. The high performance attained is ascribed to the vastly steep entropic barriers imposed by capillaries and their capacity to handle increased fields (1000 V/cm).