The glycol is, in turn, covered by a membrane made of two layers of lipids (fat-like molecules).

ECONOMIST: Medical diagnostics

The company's researchers finally devised a membrane of platinum foil sandwiched between two layers of titanium.

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But the right circumstances depend on what is happening in the lipid layers because, by itself, a single gramicidin channel is not long enough to span the membrane and thus let any sodium ions through.

ECONOMIST: Medical diagnostics