Advances in materials strategies, circuit designs, and informatics for wearable, flexible and stretchable electronics with medical and robotic applications

The future of medical electronics should be flexible, stretchable and skin-integrated. While modern electronics become increasing smaller, faster and energy efficient, the designs remain bulky and rigid due to materials and processing limitations. The miniaturization of health monitoring devices in wearable form resembles a significant progress towards the next-generation medical electronics. However, there are still key challenges in these wearable electronics associated with medical-grade sensing precision, reliable wireless powering, and materials strategy for skin-integration. Here, I present a series of systematic studies from materials strategies, circuit design to signal processing on skin-mounted electronic wearable devices. Several types of Epidermal Electronic Systems (EES) develop applications in dermatology, cardiology, rehabilitation, and wireless powering. For skin hydration measurement, fundamental studies of electrode configurations and skin-electrode impedance reveal the optimal sensor design. Furthermore, wireless operation of hydration sensor was made possible with direct integration on skin, and on porous substrates that collect and analyze sweats. Additionally, I present an epidermal multi-functional sensing platform that could provide a control-feedback loop through electromyogram and current stimulation; and a mechano-acoustic device that could capture vibrations from muscle, heart, and throat as diagnostic tools or human-machine interface. I developed a modularized epidermal radio-frequency energy transfer epidermal device to eliminate batteries and power cables for wearable electronics. Finally, I present a clinical study that validates a commercialized ESS on patients with nerve disorders for electromyography monitoring during peripheral nerve and spinal cord surgeries