Ultrastructural analysis of black lipid membranes

Abstract

Black films of egg phosphatidylcholine were investigated by electron microscopy of thin sections. A stabilizing method was developed based on a tricomplex reaction of the lipid, in order to avoid difficulties of interpretation pertaining to OsO₄ and KMnO₄-fixation techniques. Membranes were essentially trilaminar, as could be demonstrated by specimen tilting, and extensively undulated. Densitometer tracings of micrographs revealed a peak to peak width of 45 Å. Corrected for electron radiation damage this width would amount to 60Å. Taking into account the thickness of the polar layers, this would mean a total thickness of 69 Å of the native membrane.