Fabrication of wearable medical sensors heavily relies on conventional semiconductor vacuum processing. We have adopted the unique manufacturing capabilities of printed electronics and designed wearable medical devices that are soft, lightweight, and skin-like. These soft and conformable sensors significantly improve the signal-to-noise ratio (SNR) by establishing a high-fidelity sensor-skin interface. Over the past 8 years we have used different printing techniques for fabricating wearable medical sensors in two sensing modalities: bioelectronic and biophotonic. In bioelectronic sensing, we have designed and fabricated flexible and inkjet-printed gold electrode arrays which were implemented in a smart bandage for early-detection of pressure ulcers. Recently, the efficacy of the electrodes is demonstrated on conformal surfaces and on the skin to record electrocardiography (ECG) and electromyography (EMG) signals. Hybrid systems that combine flexible sensors with rigid computational components on a separate substrate provide a real-time analysis of physiological signals, with the implementation of machine-learning models for signal processing. In biophotonic sensing, we have demonstrated a flexible and printed sensor array composed of organic light-emitting diodes and organic photodiodes, which senses reflected light from tissue to determine the oxygen saturation. We use the reflectance oximeter array beyond the conventional sensing locations. The sensor is implemented to measure oxygen saturation on the forehead with 1.1% mean error and to create 2D oxygenation maps of adult forearms under pressure-cuff–induced ischemia. In addition, we present mathematical models to determine oxygenation in the presence and absence of a pulsatile arterial blood signal.

Dr. Ana Claudia Arias is a Professor at the Electrical Engineering and Computer Sciences Department at the University of California in Berkeley and a faculty director at the Berkeley Wireless Research Center (BWRC). Prior to joining the University of California she was the Manager of the Printed Electronic Devices Area and a Member of Research Staff at PARC, a Xerox Company, Palo Alto, CA. She went to PARC from Plastic Logic in Cambridge, UK where she led the semiconductor group. She received her PhD in Physics from the University of Cambridge, UK. Prior to that, she received her master and bachelor degrees in Physics from the Federal University of Paranà in Curitiba, Brazil. Her research focuses on devices based on solution processed materials and application development for flexible sensors and electronic systems. Dr. Arias is a co-founder of InkSpace Imaging, a startup company that aims to commercialized flexible MRI coils for pediatric patients.

arias.berkeley.edu