Human-made microbeads don’t always go with the flow.
Under certain conditions, the artificial particles can align themselves with a fluid’s flow and then swim upstream, researchers report May 1 in Science Advances. These particles represent a small step toward making more elaborate ones that can be used to target and treat disease, the scientists say.
“This particle is simple. It’s iron and plastic, yet it can feel flow and go against it similar to some microorganisms,” says study coauthor Jérémie Palacci, a physicist at the University of California, San Diego. “It’s mimicking what we see in nature.”