Measurement of Changes in Tissue Metabolism Using a Clark-type Oxygen Sensor

This paper presents data characterizing the ability to measure metabolic activity at a tissue interface using a Clark-type oxygen concentration sensor consisting of a microfabricated thinfilm electrode matrix overlaid with a solid-state proton conductive matrix and encapsulated in a bio-inert polytetrafluoroethylene film. HL-1 atrial myocytes were cultured onto the sensor surface. Cyclic voltammetry was utilized to characterize the sensor response over 30 minutes while the overlying tissue was subjected to either triiodothyronine or verapamil, drugs known to upregulate or downregulate, respectively, the metabolic activity of myocardial cells. Levels of percent of baseline current were calculated for both drugs, as well as for controls. The change of measured oxygen concentration was considered inversely proportional to the change in metabolic activity. Each of the drugs exerted a significant metabolic effect on the tissue, as evidenced by changes in the sensor current, thus confirming the ability to measure cellular metabolic changes at the tissue surface using the Clark-type oxygen sensor. Verapamil at 25μg/L was found to increase oxygen concentration to 135±4% as compared to control values (95±8%). Triiodothyronine at 2.5μg/L, on the other hand, decreased oxygen levels in the extracellular space to 85±9%, as compared to baseline oxygen (98±6%). The recorded metabolic effects of the tested drugs were consistent with their known physiologic effects. This sensor has possible applications in drug screening or toxicological detection.