A new tissuelike material with the squishy stiffness of fat or brain cells can be programmed to undergo delicate shape changes, akin to the unfurling of a flower’s petals.
Built with a custom-made 3-D printer by scientists at the University of Oxford in England, the “droplet network” comprises tens of thousands of tiny water droplets connected by lipid layers. Similar artificial tissues might one day serve as scaffolding for failing tissues or be used to deliver drugs to places in the body, the team reports in the April 5 Science.
To create the squishy, raftlike networks, the printer squirts a layer of water droplets into an oily solution. Lipids in the oil gather around microscopic water droplets like a cell’s membrane. The resulting millimeter-sized network of water droplets can be tweaked for specific functions, such as conducting an electrical signal at lightning speed, as a nerve cell does.
The researchers then put different concentrations of a compound such as salt into droplets in different sections of the network to spur a flow of water from one area to another. As one area of the network swells and another shrinks, the network deforms, going from flat to curved.
A droplet network printed in a flattened flowerlike form comes to life, spontaneously folding into a hollow sphere as water moves from the blue to the yellow droplets. Credit: courtesy of Gabriel Villar, Alexander D. Graham and Hagan Bayley/Univ. of Oxford