A Virtual Impactor for Hydrodynamic Particle Classification

We demonstrate a passive hydrodynamic particle sorter, a micromachined virtual impactor, for classifying biological substances according to their size. The virtual impactor can classify particles from a fully chaotic mixture composed of various sized particle. The virtual impactor is fabricated through simple silicon bulk micromachining. For preliminary performance test, monodispersed V653 cells with diameter of 10 μm were classified. Percent deviation of the experimental result was 13% compared to the theoretical value. For verifying collection efficiency of the particle sorter, polystyrene beads with diameters of 3 μm and 15 μm were sorted. Collection efficiency of 3 μm polystyrene beads was 68%.