Printed electronics have been attracting much attention as a new sensor manufacturing technology for IoT society. This paper introduces various flexible organic sensors based on organic materials with printing methods, focusing on the research and development. The specific sensors we describe include temperature sensors, pressure sensors, and humidity sensors as well as a biosensor, showing each sensor‘s construction and characteristics. In addition, we will introduce several applications to wearable sensors such as body temperature, pulse wave and lactate monitoring for healthcare.

Conventionally, in order to measure the strain of the rigid, such as metal, the strain gauges are widely used. The strain measurement of the flexible object, and a wide dynamic range（for example 100％ or more） strain sensor are required. Flexible strain sensor is expected to realize a variety of technologies. For example, measurement applications, human interface, smart wear, skin-motion monitoring, and robotic skin. We have developed a stretchable strain sensor C-STRETCH®, used the compounding techniques of elastomer and elastic conductive materials. This sensor is wide dynamic range（up to 200％ elongation）, very soft, very thin film, high responsiveness, and excellent measurement accuracy.

One of the major goals in the field of tissue-interfaced electronics is an efficient sensing or treatment by taking advantage of the proximity to the tissue, while reducing the burden on the user as much as possible. In order to achieve this goal, a wide range of innovative medical devices have been developed beyond the boundaries between academic and industrial fields in recent years. In this column, we will outline the recent trends mainly from the viewpoints of technological disciplines such as materials mechanics, biomaterials science and wireless communication engineering.