Patent ID: 7261859

Claim:
A microstructure for fluids provided in a rotatable disk comprising: a first U-shaped volume-defining structure comprising: a first arm connected at or near its upper end to an entrance port wherein the lower end of said first arm is further from the center of said disk than said entrance port; a second arm connected at or near the upper end to a first waste channel, a sample inlet or a vent via a reservoir for fluid; and a base positioned further from said center of said disk than said first and second arms, wherein said base connects the lower ends of said first and second arms and wherein at least the first arm of the first U-shaped structure is adapted to drive fluid flow by capillary action from the entrance port into the first U-Shaped structure; a second U-shaped chamber comprising: an inlet arm, wherein said inlet arm is connected to said base of the U-shaped volume defining structure, at or near to the upper end of said inlet arm, an outlet arm, wherein said outlet arm is connected at or near its upper end to a second waste channel; and a base, wherein said base connects the lower end of said inlet arm to the lower end of said outlet arm, and said base is further from, or the same distance from, the center of said disk than the lower ends of said inlet and outlet arms of said U-shaped chamber; and a barrier means for preventing capillary action between the first U-shaped volume defining structure and the second U-shaped chamber, wherein the barrier means comprises a hydrophobic break.