Weaving New Smart Objects: Actuation and Sensing at a Single Electroactive Interface

The peculiar properties of electroactive polymers mark them as protagonists in the bioelectronic research field, with application in point-of-care devices, wearable electronics, neuroscience, cell biology, and more. They have been successfully employed for the design of both sensing and actuating interfaces, which exert complementary functions but benefit from common electrochemical mechanisms unique to these materials. The question is: to what extent sensing and actuating capabilities can be integrated within a single electrochemical transducer? The simultaneous pH detection and pH-controlled release of a model dye are investigated using screen-printed textiles for wearable applications. The transducer is based on poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and is specifically functionalized to create a two-terminal pH sensor and subsequently loaded with the anionic dye. Simultaneous pH sensing and controlled dye release into the electrolytic solution are demonstrated via electrical and spectrophotometric techniques, while the local release of the dye is confirmed through scanning electrochemical microscopy. The findings confirm that the acquisition of a quantitative analytical signal and the release of the dye do not interfere with each other and can take place simultaneously at the same electrochemical interface. This opens new perspectives for the development of hybrid sensing and drug delivery systems.