Q-lipid-containing membranes show high in-plane conductivity using a membrane-on-a-chip setup

The light-driven reactions of photosynthesis as well as the mitochondrial power
supply are located in specialized membranes containing a high fraction of
redox-active lipids. In-plane charge transfer along such cell membranes is
currently thought to be facilitated by the diffusion of redox lipids and proteins.
Using a membrane on-a-chip setup, we show here that redox-active model membranes can sustain surprisingly high currents (mA) in-plane at distances of 25 mm.
We also show the same phenomenon in free-standing monolayers at the air-water
interface once the film is compressed such that the distance between redox centers is below 1 nm. Our data suggest that charge transfer within cell walls hosting
electron transfer chains could be enabled by the coupling of redox-lipids via
simultaneous electron and proton in-plane hopping, similar to conductive polymers. This has major implications for our understanding of the role of lipid membranes, suggesting that Q-lipid-containing membranes may be essential for
evolving the complex redox machineries of life.