Abstract
This study aims to construct a multilayer microfluidic device, with which morphology, and electrophysiological signal could be monitored and recorded simultaneously. The device integrate both photoresist and ITO glass substrate, such that electrical stimulation can also be applied to cells above ITO electrodes. In order to achieve the above purpose, several processes have been completed. 1. Transparent ITO electrodes were used in order to measure electrophysiological signal. 2. The pillars and cell-trapping gap structure were defined through a positive photoresist, which served as a sacrificial layer. 3. A SU-8 (negative photoresist) was furthermore stacked to form the cell-guiding channels, which have a specific aspect ratio and a branch-channel angle. The multilayer microfluidic device was then fabricated for guiding neurons to ITO electrodes. Research results are as follows: 1. This study has successfully fabricated the microfluidic device, which should be able to guide and trap living cells on top of the ITO electrodes. 2. The electrophysiological signal of the zebrafish heart has been successfully measured by the device in the study. However, the spike activity of neurons was not able to be detected, probably because the noise of measurement instrument was not well controlled. 3. In the cells cytotoxicity test, the neurons could be cultured on the photoresist for at least 14 days. This proves the biocompatibility of the proposed device. 4. Although the cell-guiding channel could successfully deliver the microbeads to the cell trapping holes, the result was not the same as the computer simulation. This is possibly due to the uncontrollable fabrication variation. 5. When testing the device with the neurons, it was found that the cell-trapping gap failed to trap the neurons. It was found that the neurons was squeezed to pass the cell gap due to the high fluid speed. The future researcher may pay more attention to slow down the fluid speed, specific methods include reducing the difference of the potential, prolonging the channel length, or increasing the resistance of the fluid in order to effectively slow down the fluid speed.