Daily management of arteriovenous fistula for dialysis patients is crucially important because it sometimes leads to stenosis and obstruction. Numerous shortcomings are associated with management techniques used today. Aside from being invasive, they also require the use of inspection, auscultation, and palpation. Moreover, they rely on the extensive experience of technicians. Actually, definite diagnosis can be made using angiography, but angiography entails difficulties associated with radiation and bulky equipment. To overcome these difficulties posed by current management techniques, we proposed an optical imaging technique. Unfortunately, the related apparatus was too large and heavy for bedside use. This paper therefore explains the possibility of clinical application of our novel technique using compact and light apparatus. Contrast of blood vessel transillumination images is intensified with two wavelengths used for measurements. Results indicate improved accuracy of inner diameter measurements of blood vessels. This study confirmed the possibility of applying this technique in medical settings to achieve continuous management of AV fistula.

A CMOS-based optical powering platform is proposed and demonstrated. Adopting an operation scheme with “charge and intermittent operation”, we realized the optical powering platform that can drive blue LED and other electronics operating at 3V or higher. The minimum required area for solar cell system is as small as 1 mm², and an implantable optical stimulation device for optogenetics with a volume of 1 mm³ was realized. It was also demonstrated that the proposed system is compatible with sequential operation, which is essential for intelligent biosensing and other applications including IoT and IoE (Internet of Everything) technology.

In this paper, we report a method of fabricating an implantable image sensor equipped a bandpass hybrid filter for highly sensitive fluorescence observation. A hybrid filter that combines an interference filter and an absorption filter enables a high excitation light removal performance in an implantable image sensor that does not use a lens. In this study, a thin hybrid filter was successfully mounted on the image sensor using the transfer method by using a laser lift-off technique. The transferred filter has no crack. It was demonstrated that the prototype device exhibited high excitation light removal performance and was able to acquire a fluorescent image with high contrast.

Detection performance of filter-free fluorescence sensors in the near-ultraviolet region has improved in this study. Thinner polycrystalline-Si film and indium tin oxide film were introduced as materials of photogate which required high transparency for sensitive measurement. Optical property of the photogate material was evaluated. Filter-free fluorescence sensors which have photogates with high optical transmittance were fabricated based on standard CMOS process. As results of a demonstration which emulates separate detection of excitation light and fluorescence by the fabricated filter-free sensors, detection performance in the near-ultraviolet region has improved a hundredfold compared to a previous sensor.

Sweat is a biomarker-rich body fluid that is most accessible without blood sampling among others. Although a number of sweat content monitors have been reported, it is still difficult to eliminate negative influences induced by changes in secretion quantity, evaporation, bacteria, and so on. One of the promising approaches to solve this problem is transporting the whole secretion to the sensing device, under the controlled conditions of the skin's surface. Recently, a sweat lactic acid monitoring system based on the continuous flow at the skin's surface has been reported. In this paper, the structure of the lactic acid monitoring system and the latest applications in sports and medical fields are reviewed in detail.

This paper describes the effects of surface modification process using oxygen plasma treatment to form molybdenum (Mo) electrodes on a poly(L-lactic acid) (PLLA) substrate. The oxygen plasma treatment was capable of physical and chemical modifications as increasing surface roughness and polar groups at the surface of the PLLA substrates. These physical and chemical modifications affected to improve the adhesiveness at the Mo/PLLA interface. Laser ablation enabled selective removal of Mo thin-layer on the PLLA substrates. Bio-resorbable and absorbable materials can potentially lead to revolutionary change in implantable medical electronics.