MXene quantum dot within natural 3D watermelon peel matrix for biocompatible flexible sensing platform

Environmentally friendly biomimetic materials with good deformability, high pressure-sensitive performance, and excellent biocompatibility are highly attractive for health monitoring, but to simultaneously meet these requirements is a formidable challenge. In this study, biocompatible MXene quantum dot (MQD)/watermelon peel (WMP) aerogels were obtained by immersing freeze-dried fresh watermelon peel into the quantum dot dispersion. The resulting bio-aerogels with a three-dimensional (3D) porous network structure exhibited a low in elasticity modulus (0.03 MPa) and limit of detection (0.4 Pa) and it showed biocompatibility. With a maximum pressure-sensitive response of 323 kPa^－1, the 3D porous MQD/WMP aerogels exhibited good stability. In addition, the sensing signals could be displayed on mobile phones through a Bluetooth module to monitor human motion (pulse, sound, and walking) in real time. More importantly, the MQD/WMP aerogels exhibited excellent biocompatibility in a cytotoxicity test, thus decreasing the safety risk when they are applied to human skin. The finding in this study will facilitate the fabrication of high-performance biomimetic MXene active matrices, which are derived from natural biological materials, for flexible electronics.