Yuta Nakashima

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.

Microfluidic device for axonal elongation control

This paper presents a novel microfluidic device for controlling axonal elongation dynamically by releasing nerve growth factor (NGF) onto a nerve cell. The presented device consists of nano-holes for NGF release and a micro valve for its release control. The amount of NGF that stimulate cells can be controlled very precisely by opening and closing the microvalve. Experiments using a fluorescent solution showed that constant chemical release through the nano-holes was successfully controlled by opening and closing the microvalve at about 2 Hz. This result indicates that the switching control of the microvalve will generate desired concentration of chemicals released from the nano-holes. Moreover, axonal guidance was tested on the fabricated device. We succeeded in guiding an axon of the cell in the direction of the nano-hole array along the NGF concentration gradient.