Scientists Develop New Thin Material, Performs Like Cell Membranes

Scientists from the Department of Energy's Pacific Northwest National Laboratory have developed a new thin material that capable of performing like cell membranes found in nature.

The new material, described in a paper published in the journal Nature Communications, is made up of lipid-like peptoids. This kind of peptoids has the ability to assemble itself into a thinner sheet but more stable than a soap bubble.

Cell membranes are made up of thin sheets of fat molecules called lipids. Lipid molecules are long and mostly straight, with their fatty ends pointed toward each other and their water-like ends pointed out. This arrangement is called lipid bilayer and is essentially a sheet that envelops the contents of the cell.

In order to mimic cell membranes, researchers used a synthetic molecule called peptoids because they are cheap, versatile and customizable. The researchers designed each base peptoid to be a long molecule with one end water-loving and the other end fat-loving, just like the lipid molecules in cell membrane.

After producing a lipid-like peptoid, the researchers put the synthetic molecule into a liquid solution. The molecules spontaneously crystallized and formed into a nanomembrane, a straight-edged sheet as thin as cell membrane. The researchers noted that the nanomembranes maintained their structure in water or alcohol, at different temperatures, in solutions with high or low pH, or high concentrations of salts.

Furthermore, the lipid-like peptoid nanomembrane thickened up when a touch of sodium chloride salt was added. Salt is involved in the last step in many signaling sequences and causes real cell membranes to thicken up. As the researchers added more salt, the nanomembrane continued to thicken up, reaching about 125 percent of their original thickness in the range of salt concentrations they tested.

According to a press release, the new lipid-like peptoid has the ability to hold proteins with different functions while still having its core structure intact. Additionally, the nanomembrane is capable of repairing itself after being cut.

With their findings, the researchers believe that the new thin material they have developed has potential in water filters, sensors, drug delivery and especially fuel cells or other energy applications.