Now, 3-D printer to build synthetic body tissues

Oxford scientists have developed a custom-built programmable 3D printer to create artificial living tissues.
The new type of material used in the printer consists of thousands of connected water droplets, encapsulated within lipid films, which can perform several of the functions of the cells inside our bodies.
These printed 'droplet networks' could be used for delivering drugs to places where they are needed and potentially one day replacing or interfacing with damaged human tissues.
Because droplet networks are entirely synthetic, have no genome and do not replicate, they avoid some of the problems associated with other approaches to creating artificial tissues - such as those that use stem cells.

The team reported their findings in the journal Science.
"We aren't trying to make materials that faithfully resemble tissues but rather structures that can carry out the functions of tissues," said Professor Hagan Bayley of Oxford University's Department of Chemistry, who led the research.

"We've shown that it is possible to create networks of tens of thousands of connected droplets. The droplets can be printed with protein pores to form pathways through the network that mimic nerves and are able to transmit electrical signals from one side of a network to the other," said Bayley.
Each droplet is an aqueous compartment about 50 microns in diameter. Although this is around five times larger than living cells the researchers believe there is no reason why they could not be made smaller. The networks remain stable for weeks.

"Conventional 3D printers aren't up to the job of creating these droplet networks, so we custom built one in our Oxford lab to do it," Bayley said in an Oxford statement.
"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. For our experiments we used two different types of droplet, but there's no reason why you couldn't use 50 or more different kinds," said Bayley.
The unique 3D printer was built by Gabriel Villar, researcher in Bayley's group and the lead author of the paper.

The droplet networks can be designed to fold themselves into different shapes after printing.
"We have created a scalable way of producing a new type of soft material. The printed structures could in principle employ much of the biological machinery that enables the sophisticated behaviour of living cells and tissues," Villar said.