近年，IoT 社会に資するセンサデバイス創成の観点からプリンテッドエレクトロニクスへの期待が高まっている。フレキシブル基板に印刷法で簡便にデバイスを作製する分野であるとともに，省エネルギーかつ少量多品種の製造にも対応できる技術として注目される。本稿では，筆者らが進めている有機材料を活用したフレキシブルセンサに関して，ヘルスケア分野への応用が期待できる温度センサ，圧力センサ，および湿度センサの作製とその代表的な特性を紹介する。また，信号処理・通信回路と一体化した実用的なセンサシステムについても具体的な応用例を紹介する。

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.

This Review describes strategies for the development of flexible chemical sensors based on π -conjugated polymer transistors. The polymer transistors are functionalized with self-assembled molecular recognition materials such as a molecularly imprinted polymer for the selective detection of a specific analyte and a selfassembled monolayer for the cross-reactive detection of multi-analytes. Indeed, the functionalized polymer transistor-based chemical sensors successfully detected biomarkers including amino acids and oxyanions in real samples. Hence, we believe that the realization of polymer-based electronic devices utilizing functional organic thin films could pave the way for wearable chemical devices in real-world scenarios.