Fabrication of Injection and Switching Valve for Whole Blood Control

Abstract

In order to fabricate a medical μTAS, microvalves which can control blood flow are indispensable. Blood clotting and blood cell adhesion to microchannels of the microvalve are actual problems. The channel structure of the microvalve is also important to avoid clotting. We fabricated microchannel coated with Parylene C having convex and round corners, and observed the blood flow running in them. The flow in the microchannel having round corners is uniform and blood cell adhesion is not observed. Sample injection and switching pneumatic microvalves having one inlet — four outlets were fabricated. Channel parts of these valves can be separated from the actuator part to realize partly disposable structure. The on/off ratio of these valves is larger than 10⁵.