Real-time Intracellular Oxygen Assay

Molecular oxygen is the key substrate of aerobic metabolism. Knowledge of cell oxygenation is therefore central to a detailed understanding of the cellular metabolic response to a particular treatment or manipulation. Traditionally intracellular measurements have proven very difficult, requiring the use of invasive, laborious, low-throughput, technically challenging techniques which in turn have limited the use of such measurements within biological research. Using a MitoXpress® Intra probe researchers can, for the first time, monitor in real time molecular oxygen within the cell monolayer on a plate reader in a non-invasive, high-throughput manner. 

MitoXpress® Intra  is a nanoparticulate metalloporphryin-based, phosphorescent, oxygen sensitive probe that is used to monitor intracellular oxygen in populations of live mammalian cells by plate-based, time-resolved fluorometry. The assay is based on the ability of molecular oxygen to quench the excited state of the probe. The probe is taken up via non-specific energy dependent endocytosis and, after washing, the cells are monitored on a time-resolved fluorescence plate reader. Probe phosphorescence is quenched by intracellular oxygen in a non-chemical, reversible manner allowing the measurement of average intracellular oxygen levels and facilitating real-time monitoring of relative changes in cellular oxygen consumption. Probe signal increases with a reduction in intracellular oxygen and decreases with an increase in intracellular oxygen. 

The MitoXpress® Intra assay is optimized for use on standard 96 / 384-well plates and time resolved fluorescence plate readers enabling high throughput analysis of multiple samples in parallel. Data produced from the chemically stable, inert MitoXpress® Intra probe is complementary to other intracellular parameters, such as ROS and mitochondrial membrane potential.