Fabrication of Micro Fluidic Chip with Micro-Injection Port by Ink-Jet Rapid Prototyping Method and Its Evaluation

It is important to reduce consumption of biomedical reagent, since some of them are quite expensive or some may cause environmental pollution. There have been reported on the biochemical micro-chips in the field of μ-TAS (micro total analysis systems), and they contributed to reduce the amount of sample liquids as well as reagent. However, most of the reagents are injected into the chip from outside through a tube. There is large dead volume in such operation. Therefore, here we propose a novel micro-injection port to minimize the dead volume. We employed a micro-valve which utilizes thermal sol-gel transformation of thermosensitive hydrogel. The valve is closed by heating the microelectrode. The three-dimensional microchannel structure is fabricated by the newly developed microfabrication technique employing the Ink-jet Rapid Prototyping Method. We succeeded in reducing consumption of reagent for more than 99% compared with the conventional operation.