Self-Healing Chemical Nanosensors

Soft and flexible chemical nanosensors offer new applications by satisfying several mechanical requirements, including conformal attachment to deformable objects, and softness. However, devices with these properties are susceptible to mechanical/structural damage such as cracks and scratches lowering their performance and durability. To address this issue, one can mimic biological systems by introducing a self-healing capability - a vital property for many organisms in nature - into flexible and soft devices, allowing the recovery of damages without external intervention. We introduce an intrinsic and fully self-healing chemically-sensitive field-effect transistor (FET) based on graphene components with high electrical performances which is fabricated by a facile approach. Its structural and electrical properties can remarkably be self-recovered in room condition after multiple cycles of micro-sized damage and even a complete cut of the device. Moreover, the sensing abilities of our self-healable FETs, both for physical (e.g., temperature) or chemical (e.g., humidity) stimuli, can be demonstrated. Fig. 1 shows the use of the transistor as an ultrathin (~3 µm) skin tattoo for monitoring the hydration level of skin. Higher I_on and Lower V_th were obtained with higher hydration levels. Most importantly, the device could recover its sensing ability after structural damages. The self-healing and stretchable FET-based nanosensors array was further demonstrated for in situ analysis of skin chemical and physical environments facilitating personalized and continuous physiological and clinical investigations.