Epidermal electronic systems for detecting electrophysiological signals, sensing, therapy, and drug delivery are at the forefront of man-machine interfaces in healthcare. The development of multifunctional bio applications with minimal invasiveness, biocompatibility, and stable electrical performance under various mechanical deformations of biological tissues remains a challenge. Using natural silk protein and carbon nanotubes (CNTs), an epidermal electronic tattoo (E-tattoo) system for multifunctional applications is proposed in this study. These challenges can be addressed by dispersing highly conductive CNTs on biocompatible silk nanofibrous networks with porous surfaces to build ultrathin electronic patches that adhere to the skin. A bio capacitor that exhibits frequency-dependent capacitances (up to 350 pF at 5 kHz), a stimulator for drug delivery, and real-time charge generation with the touch of a finger are part of a system that incorporates optically active heaters, a bio capacitor, and a stimulator for drug delivery. Using an SNF/CNT-based triboelectric nanogenerator E-tattoo, multiple bare-finger touches can generate charges that are stored in the capacitor (0.23 V for 200 touches). This device is better than a commercial band-aid at transmitting water vapor at 115.04 g m-2 d-1, due to the micro/nanopores in the NF network. It is also capable of sensing ethanol. Multicomponent integrated ultrathin and epidermal electronics can be constructed using the developed E-tattoo capacitor. A next-generation electronic platform for wearables and epidermal bio applications can be developed using this E-tattoo strategy.
