Membrane-Length Amphiphiles Exhibiting Structural Simplicity and Ion Channel Activity

A number of synthetic ion channels have been reported in recent years that incorporate unusual or sophisticated design elements. The present work demonstrates that extremely simple compounds can function as ion channels (insert in bilayers, exhibit open-close behavior) if they meet minimum criteria. A simple membrane spanning structure may function as a channel if 1) it possesses polar head-groups (is bolaamphiphilic), 2) possesses a "central relay," and 3) channel function (open-close behavior) must be detected after insertion of the amphiphile directly into the aqueous liposomal or cellular suspension. We show here compounds that are simple spans to which we have given the name "aplosspan" (from the Greek alpha pi gamma o sigma + span) that met these criteria. They are similar to, but simpler than, structures reported in the literatures that incorporate more complex design features.