In this paper, we report on a proof-of-concept level energy harvester device that could earn electric power of 0.093 µW/cm² by the fluidic motion in a PDMS (polydimethylsiloxane) micro fluidic channel placed on a silicon substrate with built-in permanent electrical charges or so-called electrets. Targeting implantable medical devices such as respiratory pace-maker, the heart beat or aspiration is thought to be the source of motion as a final shape of the energy harvesting system.

Kinesin is a motor protein that transport organelles and proteins by repeating 8 nm discrete steps on a microtubule in eukaryotic cells. The mechanism of kinesin motility coupled with the hydrolysis of adenosine triphosphate (ATP) is of great interest to researchers in biophysics. However, it is still poorly understood when kinesin heads make a step during the ATP hydrolysis and when adenosine diphosphate (ADP) is released from kinesin. In this study, we propose a simultaneous measurement of displacements of kinesin and attachment/detachment of fluorescently-labeled ATP (fATP) using Linear-shaped Zero-Mode Waveguides (LZMWs) that enables to use high concentration of fluorescent molecules for single molecule observation. To this end, we designed LZMWs based on FEM simulation and optimized a fabrication process by electron beam lithography and lift-off process. Assay procedure was established by introducing microtubules into LZMWs utilizing gliding motility. Simultaneous observation in LZMWs revealed that motility of kinesin was preserved and single fATP molecules were visualized under the concentration of 250 nM, which is about ten times higher than in conventional Total Internal Reflection Fluorescence Microscopy (TIRFM).

A new fabrication process of a superrepellent surface using a doubly reentrant structure pillar array was developed. The proposed process applying a soft-lithography is simple, low-cost, and mass-productive process compared to the conventional process. It enables to fabricate a doubly reentrant structure pillar array on glass, silicon, and PDMS substrates.

There are various potentially hazardous particles dispersed in various environment, such as virus, exhaust gas, PM 0.1 and 2.5, endospore of bacteria, etc. One of the key issues to monitor the presence of such the particles is a development of particle sensor, which should work continuously for a long time. In order to realize such type of sensor, we have proposed and experimentally demonstrated a clogging-free sampling method for continuous sampling and sensing operation by applying liquid-gate concept. We fabricated a test device and evaluated using carbon toner as a model of carbon particulate in atmospheric air. As a result, it was still primitive, we successfully proofed the concept of liquid gate sampling as expected.

In this work, an enhanced performance of an enzymatic chemo-mechanical actuator that can convert the chemical energy of glucose into mechanical energy for autonomous drug release without an electrical power is reported. The novel biochemical approach is based on increasing the decompression rate in a “vacuum unit” by fabricating enzyme co-immobilized membrane by multiple enzymes. Among the enzymes (glucose oxidase (GOD), pyranose oxidase (POD), alcohol oxidase (AOD)), which can oxidize glucose and/or glucono-1.5-lactone evaluated in co-immobilization designs within the vacuum unit, the highest decompression was obtained with POD+GOD, which was 3 times higher than that of the conventional organic engine with only GOD. Furthermore, the decompression rate of -7.4 Pa･cm³/sec in the vacuum unit necessary to drive the drug release system was obtained at 10 mmol/L glucose, which is close to the human blood sugar level. In conclusion, the vacuum unit is a promising device for development of a chemo- mechanical system driven by human blood sugar for the diabetes treatment.