How do I detect mitochondria?

Mitochondria are smooth and elongated cell bodies that are considered as the power house of the cell. Depending on the cell type, the number of mitochondria can vary. For instance, mitochondria are absent in RBCs, whereas 500-2000 mitochondria are present in hepatocytes.

There are mitochondria specific fluorescent dyes, which specifically stains mitochondria in the live cells. After staining, mitochondria can be analyzed through fluorescent microscope or flow cytometry.  For example, CytoFix Red stains mitochondria specifically, independent of mitochondrial membrane potential. One advantage of CytoFix Red is that the stained cells even after fixation would maintain fluorescence as it stains independent of mitochondrial membrane potential, which would be lost during fixation. To monitor the functioning of cells, specifically the mitochondria, membrane potential-dependent probes are required. For example, JC-10 is membrane potential-dependent probe. JC-10 in a healthier cell would get accumulated in mitochondria as aggregates, wherein its emission maximum is 590nm, whereas, in apoptotic cells, JC-10 would diffuse out of mitochondria and remain as monomers, wherein its emission maximum is 525nm.

Additionally, mitochondria can be detected by immunochemistry. Fluorescent antibodies would bind specifically to the protein present in mitochondria and they could be visualized in a fluorescence microscope. Immunochemistry is performed on fixed cells. Mitochondrial antibody targets are ATP5A1, COX4, HSP60, VDAC1 etc.