ΔΨm, mitochondrial membrane potential, is an important parameter of mitochondrial function and has been used as an indicator of cell health. Variation of ΔΨm would be studied using JC-1. In healthy cells with high ΔΨm, JC-1 forms complexes known as J-aggregates. While in cells with low ΔΨm, JC-1 remains in the monomeric form. When excited at 510 nm, JC-1 monomers emit a green fluorescence with a maximum at ~527 nm. Aggregates of JC-1 emit an orange-red fluorescence with a maximum at ~590 nm.