An open space diffusive filter for simultaneous species retrieval and separation.

We present a novel method for the local retrieval of surface bound species and their rapid in-line separation using an open space microfluidic device. Separation can be performed in less than 30 seconds using the difference in diffusivities within parallel microfluidic flows. As a proof-of-principle, we report the rapid and efficient filtration of polystyrene beads from small molecules, and surface bound red blood cells from dimethyl sulphoxide for antigen typing.