Design and Fabrication of a PDMS/Parylene Microvalve for the Treatment of Hydrocephalus

We present a novel microvalve for the treatment of a pathological condition, i.e., hydrocephalus. This microvalve is made of polydimethylsiloxane/Parylene composite layer which has a 3-D dome petal shape. This geometry enables the microvalve to rectify fluid flow in the forward and backward directions. New microfabrication techniques such as dome-shaped SU-8 mold fabrication and excimer laser machining for valve opening have been investigated to build the proposed microvalve. The pressure drop versus flow rate characteristics of the fabricated microvalve was investigated through in vitro flow tests. The flow test results showed that a 10 x 10 microvalve array with a cross-cut opening shape (200 mu m x 60 mu m) was found to be optimal for the treatment of hydrocephalus.