Mitochondrial membrane potential (ΔΨm) is a critical indicator of mitochondrial function and cellular health. Changes in ΔΨm are associated with early stages of apoptosis, mitochondrial dysfunction, and various disease states. Accurate and sensitive measurement of ΔΨm is essential for understanding cellular metabolism, drug responses, and toxicity mechanisms.

TMRE (tetramethylrhodamine ethyl ester) is a cell-permeable, red-orange fluorescent dye that accumulates in the mitochondrial matrix in proportion to the mitochondrial membrane potential (ΔψM). In healthy mitochondria with intact membrane potential, TMRE is efficiently taken up, resulting in strong fluorescence. When mitochondrial membrane potential decreases—due to damage or depolarization—TMRE is released, and fluorescence intensity diminishes accordingly. Therefore, TMRE fluorescence intensity serves as a reliable indicator of mitochondrial membrane potential status.

The RayBio^® TMRE Mitochondrial Membrane Potential Assay Kit is an in vitro fluorescent assay designed for use with live cells. The assay enables detection and quantification of mitochondrial membrane potential changes, providing a reliable assessment of mitochondrial health under a broad range of experimental conditions. It is compatible with microplate spectrophotometry, fluorescent microscopy, and flow cytometry.

• Accurate and sensitive
• Compatible with fluorescence microscopy
• Works with flow cytometry
• Suitable for microplate spectrophotometry

• Fluorescent microplate reader, fluorescent microscope, or flow cytometer
  • Microplate reader/microscope must be capable of reading Ex/Em: 549/575 nm
  • Flow cytometer must have a blue laser capable of measuring the PE channel

• General tissue culture supplies
• PBS
• FBS (Fetal Bovine Serum)
• If using a microplate reader, sterile 96-well clear bottom, dark sided microplates with lids
• If using a microscope, sterile 8-well chamber slides w/ removable wells or 96-well microplates and microscope slides
• If using a flow cytometer, sterile 12-well culture plates with lids and FACS tubes
• Adjustable pipettes (1–1000 μL)

Contact our technical support team for questions about compatibility: (techsupport@raybiotech.com)

1. Thaw and mix TMRE and FCCP reagents.
2. Dilute TMRE in culture medium.
3. Seed cells in a 96-well plate.
4. Add FCCP to positive control wells.
5. Remove supernatants from wells.
6. Add TMRE staining solution to wells.
7. Incubate cells with TMRE staining solution.
8. Measure fluorescence using a microplate reader, fluorescent microscope, or flow cytometer.