Biochemistry. Molecules that increase the permeability of lipid bilayer membranes to specific ions. Many ionophores are antibiotics. There are two classes of ionophores, carriers and channels. Carriers (like valinomycin) form cage like structures around specific ions and move freely within the hydrophobic regions of the bilayer. Channels (like gramicidin) form continuous aqueous pores through the bilayer, allowing ions to diffuse through.