A technique relates sorting entities. The entities are introduced into a nanopillar array. The entities include a first population and a second population, and the nanopillar array includes nanopillars arranged to have a gap separating one from another. The nanopillars are ordered to have an array angle relative to a fluid flow direction. The entities are sorted through the nanopillar array by transporting the first population of the entities less than a predetermined size in a first direction and by transporting the second population of the entities at least the predetermined size in a second direction different from the first direction. The nanopillar array is configured to employ the gap with a gap size less than 300 nanometers in order to sort the entities having a sub-100 nanometer size.