A Planar Microfabricated Fluid Filter

Many blood tests must be performed on plasma without cellular matter present. In the standard laboratory protocol, pure plasma is obtained through centrifugation. In order to produce a miniaturized blood sensor, a method to separate plasma other than centrifugation is needed. We describe the design, fabrication, and testing of a fluid filter that fulfills this need, and also has some features of general interest. Results from a particular device show that we can easily remove 16/spl mu/m diameter spheres from the fluid. This filter can be reusable, can potentially remove particles as small as 0.1 /spl mu/m, and is easily fabricated.