Fabrication of intrinsically conductive, durable and biocompatible liquid metal-CNT-polymer composite electrode for healthcare applications

Abstract

Conventional electronic (e-) skins are a class of thin-film electronics mainly fabricated in laboratories or factories, which is incapable of rapid and simple customization for personalized healthcare. Here, we introduce a new class of e-tattoos that can be directly implemented on the skin by facile one-step coating with various designs at multi-scale depending on the purpose of the user without substrate. E-tattoo is realized by attaching Pt-decorated carbon nanotube and polymer on gallium-based liquid-metal particles (CMP) to impose intrinsic electrical conductivity and mechanical durability. Tuning the CMP suspension to have low-zeta potential, excellent wettability, and high-vapor pressure enables conformal and intimate assembly of particles directly on the skin in 10 seconds. Low-cost, ease of preparation, on-skin compatibility, and multifunctionality of CMP make it highly suitable for e-tattoo. Demonstrations of electrical muscle stimulator, photothermal patch, motion artifact-free electrophysiological sensor, and electrochemical biosensor validate the simplicity, versatility, and reliability of the e-tattoo-based approach in biomedical engineering.