Researchers have created networks of water droplets that mimic some properties of cells in biological tissues. Using a three-dimensional printer, a team at the University of Oxford, UK, assembled tiny water droplets into a jelly-like material that can flex like a muscle and transmit electric signals like chains of neurons. The work is published today in Science.
These networks, which can contain up to 35,000 droplets, could one day become a scaffold for making synthetic tissues or provide a model for organ functions, says co-author Gabriel Villar of Cambridge Consultants, a technology-transfer company in Cambridge, UK. “We want to see just how far we can push the mimicry of living tissue,” he says.
The network relies on each water droplet having a lipid coating, which forms when the droplets are in a finely-tuned mix of oil and a pure lipid.
The lipid molecules have a water-loving head, which sticks to the droplet's surface, and a water-fearing tail, which pokes out into the oily solution. When two lipid-coated droplets come together, each with its carpet of water-fearing tails, they stick to each other like Velcro, forming a lipid bilayer, similar to those in cell membranes. The bilayer creates a structural and functional connection between droplets.
Although previous studies have shown that lipid-coated droplets can form such connections, their watery composition and spherical shape made them tricky to assemble. “I already made a raft of droplets that stuck together,” says biomedical engineer David Needham of the University of Southern Denmark in Odense, who was not involved in the study. “But to print them is really an achievement.”