3D printed shapes mimic living tissue
15 May 2013 by Evoluted New Media
A custom-built programmable 3D printer that can print materials with the properties of living tissues has been developed by Oxford University researchers.
The new type of printed material consists of thousands of connected water droplets, encapsulated within lipid films that are able to perform some of the same functions as our cells.
“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 at 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.”
These printed ‘droplet networks’ are entirely synthetic, have no genome and do not replicate, and thus avoid some of the rejection problems with other approaches to creating artificial tissues.
Each water droplet is around 50 microns in diameter - around five times larger than living cells but 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, said 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. 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.”
The droplet networks can be designed to fold themselves into different shapes after they’ve been printed. In one experiment, a flat network that resembled the petals of a flower was programmed to fold itself into a hollow ball. The folding resembles muscle movement and is powered by osmolality differences that generate water transfer between droplets.
Gabriel Villar, who built the printer and is lead author of the study, said: “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.”
The research is published in Science.
