Self-powered implantable electronic-skin for in situ analysis of urea/uric-acid in body fluids and the potential applications in real-time kidney-disease diagnosis

As the concentration of different biomarkers in human body fluids are an important parameter of chronic disease, wearable biosensors for in situ analysis of body fluids with high sensitivity, real-time detection, flexibility and biocompatibility have significant potential therapeutic applications. In this paper, a flexible self-powered implantable electronic-skin (e-skin) for in situ body fluids analysis (urea/uric-acid) as a real-time kidney-disease diagnoser has been proposed based on the piezo-enzymatic-reaction coupling process of ZnO nanowire arrays. It can convert the mechanical energy of body movements into a piezoelectric impulse, and the outputting piezoelectric signal contains the urea/uric-acid concentration information in body fluids. This piezoelectric-biosensing process does not need an external electricity supply or battery. The e-skin was implanted under the abdominal skin of a mouse and provided in situ analysis of the kidney-disease parameters. These results provide a new approach for developing a self-powered in situ body fluids-analysis technique for chronic-disease diagnosis.