34.4 A 4.5mm3 Deep-Tissue Ultrasonic Implantable Luminescence Oxygen Sensor

Continuous monitoring of regional tissue oxygenation (RTO) can provide therapeutic guidance for critical care patients. Current technologies for RTO assessment require tethered, wired connections or batteries, creating problems related to implantation and chronic use due to their large volume. Recently, ultrasound (US) has been demonstrated as an efficient way to wirelessly power and communicate with implantable devices deep in tissue, enabling their miniaturization [1], [2]. Here, we present a fully implantable, wireless, battery-free, real-time sensor system for deep tissue oxygen (0₂) monitoring. The system combines a luminescence sensor with US technology, achieving competitive or better O₂ resolution, the lowest power consumption and the smallest volume (4.5mm3) of any system previously demonstrated [3]-[5].