A single natural cotton fiber has been functionalized with poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) conductive polymer by a simple soaking process and used as a channel of an organic electrochemical transistor (OECT), directly interfaced with a liquid electrolyte in contact with an Ag wire gate. The device shows a stable and reproducible current modulation and has been demonstrated to be very effective for electrochemical sensing of NaCl concentration in water. The single wire cotton fiber OECT results to be a simple and low cost device, which is very attractive for wearable electronics in fitness and healthcare.

Zinc oxide (ZnO) tetrapods have been synthesized and prototypal gas sensors for volatile organic compounds (VOCs) have been realized with this sensing nanomaterial. Sensor characterization has been focused on aldehydes, such as acetaldehyde (or ethanal) and propionaldehyde (or propanal), whose detection at ppb levels is extremely important for monitoring environmental, domestic and food pollution, as well as for some sickness diagnosis and other medical applications. The response of gas sensor prototypes has been measured as a function of concentration, temperature, relative humidity and time. Good response values at ppb levels and some peculiar behaviours have been pointed out.