Synthetic Tissue Created with Water, Lipids, 3-D Printing

Synthetic tissue programmed to fold into sphere (Gabriel Villar, University of Oxford)

Biochemical researchers at University of Oxford in the U.K. developed materials from networks of water droplets inside lipid films to perform functions similar to human tissue. The team led by Oxford chemistry professor Hagan Bayley published its findings as the cover story in this week’s issue of the journal Science (paid subscription required).

The researchers say these tissue-like materials can serve as devices to help repair damaged tissue or deliver drugs to precise locations in the body. The materials have the consistency of soft rubber and physically resemble brain and fat tissues. Because these synthetic materials are made from water and lipids, have no genome, and do not replicate, they avoid potential problems with rejection faced by other types of bioengineered tissues.

Each droplet water droplet is about 50 micrometers — 1 micrometer equals 1 millionth of a meter — and arrayed in two different forms by a three-dimensional printer custom made for this task. “Conventional 3-D printers aren’t up to the job of creating these droplet networks, so we custom built one in our Oxford lab to do it,” says Bayley. “At the moment we’ve created networks of up to 35,000 droplets but the size of network we can make is really only limited by time and money.”

The 3-D printer was made by Gabriel Villar, a doctoral candidate in Bayley’s lab, and lead author of the Science paper. The printer emits individual water droplets with designated biochemicals, then arrayed on a moving tray into specified shapes. The droplets are separated by and adhere to a thin membrane that also provides a communication channel between droplets.

The communication capability, say the researchers, makes it possible for the material to emulate nerve cells. The team also demonstrated the material being programmed to perform folding movements, similar to muscle tissue, a result of differences in osmosis pressure that generate water transfer between droplets. One demonstration showed a flat, petal-shaped structure folded itself into a ball (illustrated at top).

The droplet network printer: two droplet generators, each with a glass capillary nozzle, next to an oil well mounted on a motorized micromanipulator. (University of Oxford)

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