The MitoXpress® Intra: Real-time Intracellular Oxygen Assay

AMSBIO has introduced MitoXpress^® Intra, a novel intracellular oxygen assay based on a 96 or 384-well fluorescence plate reader-based approach that facilitates the real-time assessment of transient changes in cell respiration, oxygen gradients and physiological responses across a range of cell models.

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.

MitoXpress^® Intra is a powerful new tool that has been shown to facilitate the real-time assessment of transient changes in cell respiration, oxygen gradients and physiological responses across a range of cell models. Specifically, it facilitates the measurement of cellular oxygenation; a critical parameter across many fields of research including hypoxia and cancer metabolism.