This paper reports on shape control of a biomimetic tube that enables mechanical stimulation of cells. The tube can be transformed from a flat state using integrated pneumatic balloon actuators that bend up when air pressure is applied. The flat and transformed tubular state are suitable for cell observation and perfusion experiments, respectively. In this study, we developed a shape control mechanism composed of a supporting structure around the tube and pneumatic balloons. The supporting structure is introduced to ensure stable long-term perfusion experiments, and pneumatic balloons can control the shape of the tube. We analyzed strain and shear stress related to mechanical stimulation of cultured cells caused by the shape control and perfusion, respectively. We expect that the improved openable microfluidic device will contribute to the advancement of in vitro drug screening technology.

Metallic thin films are essential for various device applications. Given that sensor performance highly depends on thin film thickness and optical constants, ellipsometry is an indispensable measurement technique. While a cost-effective alternative using a spectrometer exists, it is cannot simultaneously determine both thickness and optical constants. In this study, we develop and validate a machine learning model capable of simultaneously estimating film thickness and optical constants from a single reflectance spectrum, thereby extending its applicability to opaque substrates and materials for which conventional models are inadequate.

The authors have investigated a high-sensitive hydrogen pressure sensor at low pressure range. So far, we developed the vessel built-in type hydrogen pressure sensor element consisting of the zirconia structure body and the Cr-N thin film, which are not affected by hydrogen. In this study, we miniaturized the element to a 4 mm square and 3 mm thickness with a 2 mm diameter diaphragm. Its pressure response showed excellent linearity, sufficient sensitivity of about 1 mV/MPa, and stability with no significant change after 64 hours of holding at about 10 atm. In addition, a temperature sensor film was formed on the pressure sensor element, which enabled accurate simultaneous measurement of temperature changes in the pressure vessel. It can be expected as an unprecedented miniaturized pressure sensor with a temperature sensor that can be built into a pressure vessel, a joint or a pipe of hydrogen pressure system.