abstract:SkQ (10-(6'-Plastoquinonyl)decyltriphenyl-phosphonium) stands for a class of organic molecules composed of a large organic cation (often called "penetrating cation" for the ability to penetrate through lipid bilayer) with antioxidant plastoquinone attached to it. When added to a living cell, penetrating cations are distributed according to the transmembrane electrical potential difference.