Using water molecules to read electrical activity in lipid membranes

A valuable new tool in the effort to understand how cells – and neurons in particular – function.

Activity in lipid membranes
Activity in lipid membranes © J.Caillet / EPFL

EPFL scientists for the first time, are able to detect the behavior of adjacent water molecules. This enables them to map out in real time how charges are transported across and along membranes.

Specifically, they have developed a method that allows them to understand how cells – and neurons in particular – function. It could shed light on how ion channels function, along with other processes at work in membranes. This clinically viable method could potentially also be used to directly track ion activity in neurons, which would deepen researchers’ knowledge of how nerve cells work.

Each human cell is encased in a five-nanometer-thick lipid film that shields it from the encompassing condition. The layer figures out which particles and atoms can go through. In this manner, it guarantees the phone’s prosperity and soundness and enables it to impart by means of electrical signs.

Scientists at EPFL could track these moving charges continuously in a totally non-obtrusive way. As opposed to watching the films themselves, they took a gander at the encompassing water particles, which, notwithstanding keeping the layer in place, change introduction within the sight of electrical charges. So by ‘perusing’ their position, the specialists could make a dynamic map of how charges are transported over a layer.

Sylvie Roke, head of the LBP said, “Water molecules can be found wherever there are lipid membranes, which need these molecules to exist. But until now, most studies on membranes didn’t look at these molecules. We’ve shown that they contain important information.”

Scientists used a unique second-harmonic microscope with imaging efficiency of more than three orders of magnitude greater than that of existing second-harmonic microscopes to obtain images of water molecules at a time scale of 100 milliseconds. To test the lipid layers’ hydration, the analysts consolidate two lasers of a similar recurrence (femtosecond beats) in a procedure that creates photons with an alternate recurrence: this is known as second-symphonious light. It is created just at interfaces and uncovers data on the introduction of water particles.

Orly Tarun, the publication’s lead author said, “We can observe what’s happening in situ, and we don’t need to modify the environment or use bulky markers like fluorophores that would disturb water molecules’ movement.”

With this technique, the scientists watched charge changes in layers. Such vacillations were already obscure and indicate considerably more perplexing synthetic and physical conduct than is presently considered.

Scientists detailed the method in the journal Proceedings of the National Academy of Sciences (PNAS).