Piezoelectric inkjet printer technology recently has gained attention and was utilized eject particles and cells of several tens of μm scale, which is large compared to colloid used in printer ink. However, the inkjet head was originally design for color ink. Therefore, problems, such as, head clogging and trajectory error occurred. In this study, those problems were addressed, and optimal condition for stable cells ejection was verified. Furthermore, one cell per one droplet printing method was established by observing cells position on the inside of inkjet head. Finally, automatic one cell per one droplet printing system was successfully developed by processing image of the inkjet head to automatically detect cells position. The automatic one cell per one droplet printing system was successfully developed with 98% successful ratio.

In this study, we present a new fixture (self-attachable fixture) and tensile test system for measuring mechanical properties of cell sheet. To evaluate strength of cell sheet, it is the most important to measure mechanical properties of tensile mode. However, there has been no study which measured the tensile mechanical properties of cell sheet, since it has been difficult to attach a cell sheet in the tensile test system owing to the structure of the conventional fixture, and there has been no tensile test system which had a measurement range that covered the tension force range of the cell sheets. Therefore, we have addressed these problems by developing a self-attachable fixture and a tensile test system. By using developed system, we measured mechanical properties (tension, stress and initial stiffness) C2C12 of cell sheet cultured in different recipe of culture medium. The initial stiffness of cell sheet cultured in culture medium without FBS had a tendency to become stiffer. This indicates that our new fixture and test system are applicable for evaluating mechanical properties of cell sheets.

This paper proposed a Multiple Microfluidic Stream based Manipulation (MMSM) for bio-objects using micro hydrodynamics and Lab on Chip (LOC) technology. Our method can manipulate bio-objects without contact under open space, the advantages of which were experimentally confirmed in this paper. Compared with other conventional bio-manipulation methods, this method is not directly in contact with the target bio-object, and was considered as a non-invasive and soft manipulation via hydrodynamic fluids. The basic principle of this system is manipulating a micro object by controlling several micro water streams which are generated from orifices under the operating area simultaneously. By changing the parameters of the water stream such as flow rates, position and number of operating orifices, the direction and velocity of the object can be controlled. To verify this principle, we designed an open space fluid model for on-chip manipulation, and simulated force and direction of the water stream using CFD software. Then the prototype microchip with an array of 8 orifices of diameter 100 μm, and 3 types of channels of widths 100 μm, 200 μm, and 500 μm respectively were fabricated with glass. In experiments several kinds of rectilinear motion of insect ovum and micro beads were observed. The results presented in this paper showed that this multi micro fluidic stream manipulation system has the capability for MMSM.

Here we present an environmentally robust mechano-bionic system using insect dorsal vessel tissues. Although mechano-bionic systems using mammalian heart muscle cells were reported previously, these mechano-bionic systems require precise environmental control to keep the heart muscle cells contracting spontaneously. To overcome this problem, our group focused on insect dorsal vessel tissues as a novel driving source of mechano-bionic system. We have shown so far that insect dorsal vessel can be utilized as driving source that is robust over culture conditions. In this paper, as a mechano-bionic system that is robust over its operating environment, we propose a micro-actuated system that consists of insect dorsal vessel and mechanical structure fabricated by micro fabrication technology. By photolithographic technique, the components of the machine were fabricated. The excised dorsal vessel was attached to the microstructure by tweezers under the stereomicroscope. The micro-mechanical components with dorsal vessel was incubated at 25°C, and after several hours of culture, it was actuated by contraction of dorsal vessel. Using image analysis, its maximum open-end displacement and operating frequency was measured around 27μm and 0.5Hz, respectively. We successfully demonstrated in constructing the mechano-bionic system that is robust over its operating environment.