Abstract
The authors have been investigated how to use protists as living micromachines by controlling their behavior using their taxis. If we use microorganisms themselves as a living micromachine, the things they can do is very limited, such as push something, etc. Therefore, we have to develop and equip some special operation tool for each microorganism to do a special task. We once succeeded to install washer-like operation tool to paramecium, and this tool equipped paramecium could push object easier than to push it by paramecium itself. The tool equipment operation to paramecium, however, is very difficult because paramecium has soft body and we attach tool by physical fitting. On the other hand, Daphnia magna has outer shell and we can easily attach operation tool by chemical adhesion. Daphnia can also be controlled its behavior very well by using their strong positive phototaxis. In this paper, we tried to develop and make a tool and a working scheme for the highly complex task. We choose injection work for the target to prepare future medical application. First, we attached a needle on the Daphnia's back to destroy balloon by the needle. The motion controlled Daphnia could puncture the balloon made of thin plastic film using the equipped needle. Next, we developed a medical fluid injection for Daphnia. After the trials and errors, we applied a glass pipette for micro injection and forming agent to produce gas pressure as a medical fluid discharge mechanism. A motion controlled Daphnia which was equipped this injection could insert the tip of the needle and poured a medical fluid into soft jelly.
