Organic transistor-based chemical sensors with self-assembled monolayers

Numerous artificial receptors with noncovalent bonds have been developed to date, whereas chemical sensing devices combined with these receptors have not been fully established. An organic thin-film transistor (OTFT) can potentially operate as a supramolecular sensor chip by appropriately combining it with molecular recognition parts. In this review, the attempts to fabricate devices for electrical chemical sensing utilizing a self-assembled monolayer on a gate electrode or a surface of a semiconductor layer of the OTFT are described. Self-assembled scaffolds provide multi-recognition sites, leading to selective and sensitive detection. Furthermore, the OTFT functionalized with various receptors provide comprehensive sensor platforms for multiple analytes including cations, anions, electrically neutral molecules, and proteins in aqueous media. The OTFT-based sensor successfully detected analytes with size and chemical structural dependences on self-assembled receptors. Moreover, real-time continuous detection was also accomplished by the OTFT-based sensor integrated with a microfluidic system. Thus, this concept implies a promising future for applying an easy-to-use chemical sensor in practical situations by taking advantage of well-developed supramolecular interactions.