Self-powered biocompatible humidity sensor based on an electrospun anisotropic triboelectric nanogenerator for non-invasive diagnostic applications

The development of innovative devices that enables real-time monitoring of physiological activities and envi-ronmental conditions for healthcare applications has gained momentum in recent years. However, it is still a challenge to fabricate a self-sustainable wearable device with inherent comfort, long-time wearing and elec-trostatic discharge (EDS) safety for the monitoring of human-status. Herein, we developed a self-powered hu-midity sensor using an electrospun anisotropic triboelectric nanogenerator (A-TENG) composed of aligned MXene nanofibers (NFs) and cellulose acetate (CA) NFs. Importantly, such developed anisotropic structure of TENG exhibits its potential in sensitive moisture detection upon fast adsorption/desorption of water molecules due to increased pore length of prepared NFs. Moreover, it also benefits the device in reducing the EDS risks based on the working orientation of A-TENG. The practical application of detecting the skin moisture using finger-tapping is also demonstrated. Furthermore, CA NFs render superior antibacterial performance due to the high release of loaded copper nanoparticles at targeted skin surfaces, enabling long-time wearability of A-TENG. The above findings suggest that the highly ordered alignment of collected NFs is found to be favorable for the development of future-generation wearable devices.