By rethinking what happens on the surface of things, engineers at Harvard University have discovered that Bacillus subtilis biofilm colonies exhibit an unmatched ability to repel a wide range of liquids—and even vapors.

Centimeters across yet only hundreds of microns thick, such slimy bacterial coatings cling to the surfaces of everything from pipes to teeth and are notoriously resistant to antimicrobial agents. The researchers now suspect they know the secret to a biofilm’s resiliency.

Published in the Jan. 5 early edition of the Proceedings of the National Academy of Sciences (PNAS), the study holds promise for both creating bio-inspired non-wetting materials and developing better ways to eliminate harmful biofilms that can clog pipes, contaminate food production and water supply systems, and lead to infections.

“By looking at biofilms from a materials perspective rather than a cellular or biochemical one, we discovered that they have a remarkable ability to resist wetting to an extent never seen before in nature,” says lead author Alex Epstein, a graduate student at the Harvard School of Engineering and Applied Sciences (SEAS). “In fact the biofilm literally resisted our initial efforts to study it.”