Engineers have made a gas bubble with a hole in it. Tiny beads surround a sesame-seed–size ring of air that holds its shape in air-saturated water for at least 2 weeks, says Anand Bala Subramaniam of Harvard University. Hundreds of ceramic zirconia beads at the gas-water boundary lock in the shape.
To make bead-coated spherical bubbles or liquid droplets, the team first injected gas or liquid into a thin stream of particle-laden water. Squeezing those creations generated toroids, sausages, and other shapes. Each nonspherical form remains stable because its beads, jammed together by surface tension, act as a stiff shell, Subramaniam explains. Some biological structures may retain nonspherical shapes because of similar jamming of membrane components, the team suggests in the Dec. 15 Nature.
