ionophore

thumb|right|420 px|Carrier and channel ionophores (a) Carrier ionophores reversibly bind ions and carry them through cell membranes. (b) Channel ionophores create channels within cell membranes to facilitate the transport of ions.

In chemistry, an ionophore () is a chemical species that reversibly binds ions. Many ionophores are lipid-soluble entities that transport ions across the cell membrane. Ionophores catalyze ion transport across hydrophobic membranes, such as liquid polymeric membranes (carrier-based ion selective electrodes) or lipid bilayers found in the living cells or synthetic vesicles (liposomes). Structurally, an ionophore contains a hydrophilic center and a hydrophobic portion that interacts with the membrane.