Materials scientists have created a new material that performs like a cell membrane found in nature. Such a material has long been sought for applications as varied as water purification and drug delivery.
Referred to as a lipid-like peptoid (we'll unpack that in a second), the material can assemble itself into a sheet thinner, but more stable, than a soap bubble, the researchers report this week in Nature Communications. The assembled sheet can withstand being submerged in a variety of liquids and can even repair itself after damage.
"Nature is very smart. Researchers are trying to make biomimetic membranes that are stable and have certain desired properties of cell membranes," said chemist Chun-Long Chen at the Department of Energy's Pacific Northwest National Laboratory. "We believe these materials have potential in water filters, sensors, drug delivery and especially fuel cells or other energy applications."
The amazing membrane
Cell membranes are amazing materials. Made from thin sheets of fatty molecules called lipids, they are at least ten times thinner than an iridescent soap bubble and yet allow cells to collectively form organisms as diverse at bacteria, trees and people.
Cell membranes are very selective about what they let pass through, using tiny embedded proteins as gatekeepers. Membranes repair dings to their structure automatically and change thickness to pass signals from the outside environment to the cell's interior, where most of the action is.
Scientists would like to take advantage of membrane properties such as gatekeeping to make filters or signaling to make sensors. A cell-membrane-like material would have advantages over other thin materials such as graphene. For example, mimicking a cell membrane's efficient gatekeeping could result in water purifying membranes that don't require a lot of pressure or energy to push the water through.
Synthetic molecules called peptoids have caught the interest of researchers because they are cheap, versatile and customizable. They are like natural proteins, including those that embed themselves in cell membranes, and can be designed to have very specific forms and functions. So Chen and colleagues decided to see if they could design peptoids to make them more lipid-like.
Source: Pacific Northwest National Laboratory
Date: Jul 19, 2016