Repetitive measurements of physiological pH by implantable optical sensors in muscles of adult Danio rerio: preliminary results

Encapsulated optical sensors are promising tool for measurements of physiological parameters inside living organisms. In the present study we tested the possibility to apply encapsulated fluorescent sensors to measure pH in muscles of adult Danio rerio. Right after injection, the sensors detect slightly acidic pH, while after 3 h pH becomes significantly more alkaline. These fluctuations are probably related to cell damage during the injection and further wound repair. After 20 h pH of interstitial fluid was equal to 7,65, which is in between previously measured values and close to the blood pH known for other fishes.