Development and in-vivo validation of a portable phosphorescence lifetime-based fiber-optic oxygen sensor

Abstract

Oxygenation is a crucial indicator of tissue viability and function. Oxygen tension (pO 2), i.e. the amount of molecular oxygen present in the tissue is a direct result of supply (perfusion) and consumption. Thus, measurement of pO 2 is an effective method to monitor tissue viability. However, tissue oximetry sensors commonly used in clinical practice instead rely on measuring oxygen saturation (StO 2), largely due to the lack of reliable, affordable pO 2 sensing solutions. To address this issue we present a proof-of-concept design and validation of a low-cost, lifetime-based oxygen sensing fiber. The sensor consists of readily-available off-the shelf components such as a microcontroller, a light-emitting diode (LED), an avalanche photodiode (APD), a temperature sensor, as well as a bright in-house developed porphyrin molecule. The device was calibrated using a benchtop setup and evaluated in three in vivo animal models. Our findings show that the new device design in combination with the bright porphyrin has the potential to be a useful and accurate tool for measuring pO 2 in tissue, while also highlighting some of the limitations and challenges of oxygen measurements in this context.