A novel microstep device for the size separation of cells.

We report on a series of preliminary experiments investigating the applicability of a novel method for the size separation of nano- and microsized particles and cells. The working principle is based on the application of a shear-driven flow through stepwise tapered micro- or nanochannels. Size separations of mixtures of 0.5 and 1.0 μm carboxylated polystyrene beads as well as of binary mixtures of Staphylococcus aureus and Saccharomycescerevisiae cells and of S. cerevisiae and Escherichia coli cells are demonstrated.