Dissertation Talk: Wearable medical sensors enabled by printed bioelectronics and biophotonics

Seminar | December 7 | 10-11 a.m. | Cory Hall, Cory 490H (Immersion Room in Swarm Lab)

 Yasser Khan, Electrical Engineering and Computer Sciences, UC Berkeley

 Electrical Engineering and Computer Sciences (EECS)

Wearable medical sensors that can monitor biosignals have the potential to transform healthcare - they encourage healthy living by providing individuals feedback on personal vital signs and enable facile implementation of both in-hospital and in-home health monitoring. To date, fabrication of wearable medical sensors heavily relies on conventional semiconductor vacuum-processing, which is expensive and has limited large-area scalability. Taking advantage of the unique manufacturing capabilities of printed electronics, we can now design wearables that are soft, lightweight, and skin-like. These soft and conformable sensors significantly improve the signal-to-noise ratio (SNR) by establishing high-fidelity sensor-skin interfaces.

In this talk, I will discuss different printing techniques for fabricating wearable medical sensors and highlight two sensing modalities: bioelectronic and biophotonic. For bioelectronic sensing, I will focus on flexible inkjet-printed gold electrodes, and their applications in bioimpedance spectroscopy, electrocardiography (ECG), and electromyography (EMG). For biophotonic sensing, I will present our work on printed biophotonic sensors for blood and tissue oximetry that will include an all-organic optoelectronic sensor, which accurately measures pulse rate and oxygenation via transmission-mode pulse oximetry. Since transmission-mode oximetry can only be performed at the extremities of the body and requires a pulsatile arterial blood signal - printed, organic, reflection-mode oximeters will be discussed. The design, sensing methodology, and fabrication of a flexible sensor array composed of organic light-emitting diodes (OLEDs) and organic photodiodes (OPDs) will be shown, which senses reflected light from tissue to determine oxygen saturation. Finally, a key enabling technology for wearables - flexible hybrid electronics (FHE) will be presented. I will focus on the implementation of FHE in an integrated multi-sensor platform, where soft sensors are interfaced with hard silicon-based integrated circuits for wearable health monitoring.