Scientists have already used inkjet printers to "print" bacteria, yeast and even human stem cells and they are exploring how to use the office workhorse to create 3D cell structures in a tissue matrix.
If they can figure out how to create more complex tissues, they will be one step closer to creating implantable organs, a scientist said in a paper published in the journal Science on Friday.
"We’ve passed a milestone," said Paul Calvert, a material scientist at the University of Massachusetts in Dartmouth who has printed human stem cells. "We’ve shown that we can print cells and that they survive the process.
"If we can figure out how to build multiple layers of cells, then we’re one step closer to creating an organ, and the ability to make functioning tissue — even in inelegant little lumps would still be useful."
Teams of scientists in the United States, Britain and Japan have been using modified inkjet printers to print cells for several years now — everything from single cell organisms such as yeast to hamster ovary cells.
They typically empty out the ink cartridges and fill them with solutions of cells, and reconfigure the appliance so that the nozzle spews the "bio-ink" on to some kind of growth medium rather than a sheet of paper.
One of the chief advantages of the technology is that it’s a convenient, non-contact way of depositing patterns of cells. Subsequent printing cycles don’t disturb the material from previous cycles.
Calvert and his team have already printed "human stem cells".
Their challenge now is to construct simple layered structures to study the effect of proximity of different cell types on tissue development, using polymers or gels as scaffolds to separate and support the emerging tissues.
"If we can grow two different cell types together, we can see how they communicate," said Calvert, who gives a status report on the progress of the field in his Science paper.
The next step would be "to build complex three-dimensional tissues by printing the right precursors and enzymes in sequence".
Given the right sources of the precursor proteins or compatible substitutes, we can build many passive structures such as bone, ligament, cartilage and cornea," he wrote.
The day when scientists can create life-size organs from scratch using inkjet printers is probably some way off.
"I would be surprised if we could do it in 10 years. I would be disappointed if we couldn’t do it in 30," said Calvert.
But if scientists could create even a sliver of a liver or a heart this way in a laboratory, those tissues could be used for medical purposes, such as testing drugs, he noted.