Deterministic lateral displacement MEMS device for continuous blood cell separation

This work presents a new MEMS device which uses deterministic lateral displacement for the continuous separation of leukocytes (white blood cells) and erythrocytes (red blood cells). By running blood cells in laminar flow through an array of columnar obstacles, deterministic lateral displacement asserts that the path a cell follows is determined by its size. The system consists of PDMS channels with posts on glass slides. An effective separation region of 7 mm by 1.8 mm is achieved on a 1 cm by 1 cm chip. A 420 /spl mu/m lateral separation was achieved for 5 /spl mu/m and 10 /spl mu/m beads. The critical particle size for separation was found experimentally to be 8 /spl mu/m, concluded from our results using 5 /spl mu/m, 7 /spl mu/m, 8 /spl mu/m and 10 /spl mu/m polystyrene beads. Diluted whole blood and blood fraction of concentrated leukocytes were also tested with the devices in agreement with blood count results. Problem of blood cell stiction to device surfaces was investigated.