Selective uric acid sensing in biofluids for health status monitoring

Uric acid concentration is a relevant biomarker associated with health status. In this contribution, we present the development of two chemical sensors based on organic electrochemical transistor (OECT) transduction mechanism for uric acid (UA) selective monitoring. In particular, the devices were exploited for two main applications: oxidative stress determination and wound condition monitoring. Both sensors are fabricated with poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) thus benefitting of the polymer capability to catalyze analytes electro-oxidation. Oxidative stress, defined as a disturbance in the balance between the production of reactive oxygen species (free radicals) and antioxidant defences, can be estimated in real matrixes by uric acid concentration [1]. UA is detected by the OECT sensor in pig saliva and egg yolk as major antioxidant component, by means of its oxidation occurring at a gate voltage within PEDOT:PSS stability window. In hard-to-heal wounds, typically associated with particular pathologies or afflictions, it is fundamental to monitor overall wound conditions and healing stages, aiming at patient-specific therapies and faster patient recovery. For this reason, new devices have been developed by our research group to monitor pH [2] and moisture [3] in wound fluid. In this context, a Smart Bandaid Integrated with Fully Textile OECT has been fabricated, overcoming the limitations of removing the bandages and visually inspecting the wound reducing the risk of infection and the disturbance of the healing stages [4]. UA concentration has been investigated with this novel textile sensor since it represents a relevant biomarker associated with infections or necrotization processes in human tissues.