Using the printers, they are able create 3-dimensional structures, known as 'tissue scaffolds'. The shape of the scaffold determines the shape of the tissue as it grows. The structures are created by printing very thin layers of a material repeatedly on top of each other until the structure is built. Each layer is just 10 microns thick (1,000 layers equals 1cm in thickness).
This method allows larger tissues to be grown than previously possible. The reason for this is the way in which the cells are inserted into the structures.
Before being fed into the printer, the cells are suspended in a nutrient rich liquid not dissimilar to ink, which ensures their survival. The cells are then fed into the printer and seeded directly into the structure as it is built. This avoids any 'sticking to the surface' which is a major disadvantage of current methods that infuse the cells into the structure after it has been built.
"The problem is getting cells into the interior of these constructions as they naturally stick to the sides of whatever they are being inserted into. If they stick to the sides then this limits the number of cells which can grow into tissues, and the lack of penetration also limits their size. By using inkjet printing we are able to seed the cells into the construction as we build it, which means 'sticking' isn't a problem," says Professor Derby.
Professor Derby believes the potential for this technology is huge: "You could print the scaffolding to create an organ in a day," he says.
As always, this research needs some time before getting to the point where it will affect our daily lives. But when translated into a shippable product, organ printers will have some pretty amazing implications. No longer having to worry about tissue rejection or a lack of available donor organs is one obvious result, and the possibility of more accurate (and aesthetically pleasing for the recipient) reconstructive surgery was one of the drivers of the research. If more complex organs could be created (as might be possible if the scaffolding system is combined with stem cell research), one can imagine a scenario where organ replacement is a faster, safer option than organ repair (such as open-heart surgery).
But this technology would have implications beyond the medical world. For example, this technology should work equally well for building non-human muscle tissue for consumption as meat. While the comparative expense would be enormous at first, artificially-grown real meat might have some distinct advantages: it would be cruelty-free, by definition; meat factories could be anywhere, would take up much less space than cattle ranches or chicken farms, and ostensibly produce much less waste (and methane!); fields now used to grow grain for livestock could instead grow food for people, or even become CO2 sequestration sites; and control over the "seed" cells would mean that prion contaminations (leading to mad cow disease) could be completely avoided. While "vat-grown" hamburgers have been a staple of science fiction stories for awhile now, the future may instead be in "meatprinters." When McDonald's buys Epson, you'll know that this future is near.