Abstract: A method of controlling fluid flow in a channel in a microfluidic flow control device by introducing fluid to the channel, with the fluid flowing in a flow direction and controllably deforming material defining the channel in a direction perpendicular to the flow direction to control fluid flow in the channel. The channel is formed between a first plate and a second plate and controllably deforming material defining the channel comprises deforming at least one of the first and second plates. Material defining the channel extends continuously between an inlet port and an outlet port. Controllably deforming material defining the channel preferably comprises deforming the first plate into contact with a seat formed in the second plate to close the channel. The seat may be formed by a ridge having a smoothly changing profile in section across the channel. The method may be operated to generate a pumping, filtering, trapping or mixing function. Apparatus for carrying out the method is also disclosed.

Abstract: A bead trapping device for trapping beads. The device is formed from a substrate, posts extending from the substrate; the posts being patterned to form cavities between the posts, the cavities having a diameter between 0.5 &mgr;m and 200 &mgr;m; and means for loading beads onto the substrate. A method of trapping microscopic beads for analysis, the method comprising the steps of contacting a fluid containing beads with a substrate having posts extending from the substrate to form bead trapping cavities, the bead trapping cavities having a diameter between 0.5 &mgr;m and 200 &mgr;m; and loading the beads into the bead trapping cavities.

Abstract: A method of controlling fluid flow in a channel in a microfluidic flow control device by introducing fluid to the channel, with the fluid flowing in a flow direction and controllably deforming material defining the channel in a direction perpendicular to the flow direction to control fluid flow in the channel. The channel is formed between a first plate and a second plate and controllably deforming material defining the channel comprises deforming at least one of the first and second plates. Material defining the channel extends continuously between an inlet port and an outlet port. Controllably deforming material defining the channel preferably comprises deforming the first plate into contact with a seat formed in the second plate to close the channel. The seat may be formed by a ridge having a smoothly changing profile in section across the channel. The method may be operated to generate a pumping, filtering, trapping or mixing function. Apparatus for carrying out the method is also disclosed.