Oxygensensing

Oxygensensing refers to the detection and measurement of oxygen levels in a given context. It encompasses biological oxygen sensing, chemical sensing of oxygen in air and liquids, and medical and industrial applications. Accurate oxygen sensing is important for studying cellular metabolism, monitoring environmental conditions, ensuring process safety, and guiding therapeutic decisions.

Biological oxygen sensing enables organisms to respond to hypoxia. The central pathway involves hypoxia-inducible factors (HIFs). Under low oxygen, oxygen-dependent prolyl hydroxylases fail to mark HIF for degradation, allowing HIFs to regulate genes controlling angiogenesis, glycolysis, and red blood cell production. Mitochondria and reactive oxygen species participate in signaling, and tissue oxygen-sensing precision varies among cell types and physiological states.

Technically, oxygen sensing employs electrochemical methods (Clark-type sensors) where O2 reduction generates a current proportional to O2 concentration; and optical methods in which oxygen quenches luminescent or phosphorescent dyes, with lifetime measurements enabling robust readouts. Other approaches include zirconia ceramic sensors for high-temperature gas sensing and various polymer- or nanomaterial-based sensors for environmental and biomedical use. Medical devices such as pulse oximeters and transcutaneous sensors illustrate clinical oxygen sensing.

Challenges include cross-sensitivity to carbon dioxide, humidity, and temperature, as well as drift and calibration requirements. Sensor design often balances response time, selectivity, durability, and biocompatibility. Advances focus on miniaturization, implantable sensors, and multi-parameter sensing that combines oxygen with related species to provide contextual physiological or environmental information.