Fabrication of a microfluidic device for axonal growth control

A microfluidic device consisting of a hydrophobic passive microvalve and a nano-hole array used for release of axonal growth enhancement protein was fabricated and tested. The microvalve was constructed in a microchannel and driven by inlet pressure. The nano-hole array was fabricated in a SiO/sub 2/ diaphragm of 280 nm in thickness using FIB (Focused Ion Beam) etching. Each nano-hole measures 100-500 nm in diameter, and is smaller than the diameter of an axon terminal. Experiments using a fluorescent solution showed that chemicals were successfully being released through the nano-hole array and diffused onto the device surface for nerve cell culture. This result suggests that the fabricated device can make the NGF concentration gradient that is required to control axonal growth.