Electronic Tattoos for Mobile Sensing and Therapeutics

Merging human body with electronics and machines can enable internet of health (IoH), human-machine interface (HMI), as well as augmented human capabilities. However, bio-tissues are soft, curvilinear and dynamic whereas wafer-based electronics are hard, planar, and rigid. Over the past decade, stretchable high-performance inorganic electronics blossom as a result of innovative structural designs and fabrication processes. In particular, epidermal electronics, a.k.a. electronic tattoos (e-tattoos) represent a class of noninvasive stretchable circuits, sensors, and stimulators that are ultrathin, ultrasoft and skin-conformable. A work-in-progress dry and reversible adhesive based on micro-surface craters will be briefly introduced. Our group has invented a dry and freeform “cut-solder-paste” method for the time- and cost-effective rapid prototyping of wireless or very large area stretchable e-tattoos. The e-tattoos can be applied for electrophysiology (e.g. ECG, EEG, EMG, EOG, etc.), mechanophysiology (e.g. respiration, seismocardiogram, pulse pressure, etc.), thermophysiology, photoplethysmography (PPG) etc.. The e-tattoos can also be used as personalized treatment and therapeutic device. For wireless operation, we leverage Bluetooth low energy (BLE) for wireless data transfer and near field communication (NFC) for wireless charging on-the-go. A modular and reconfigurable concept will be introduced to enable the recycling of integrated circuits. A remedy for connecting ultrathin and ultrasoft e-tattoo to rigid wristwatch will be discussed. A perspective on future opportunities and challenges in this field will be offered at the end of the talk.