Print me a heart and = a set of arteries - health - 13 April 2006 - Print

Print me a heart and a set of arteries

13 April 2006=20
From New Scientist Print Edition. Sub= scribe=20 and get 4 free issues.=20
Peter Aldhous

SITTING in a culture dish, a layer of chicken heart cells beats in = synchrony.=20 But this muscle layer was not sliced from an intact heart, nor even = grown=20 laboriously in the lab. Instead, it was "printed", using a technology = that could=20 be the future of tissue engineering.

Gabor Forgacs, a biophysicist at the University of Missouri in = Columbia,=20 described his "bioprinting" technique last week at the Experimental = Biology 2006=20 meeting in San Francisco. It relies on droplets of "bioink", clumps of = cells a=20 few hundred micrometres in diameter, which Forgacs has found behave just = like a=20 liquid.

This means that droplets placed next to one another will flow = together and=20 fuse, forming layers, rings or other shapes, depending on how they were=20 deposited. To print 3D structures, Forgacs and his colleagues alternate = layers=20 of supporting gel, dubbed "biopaper", with the bioink droplets. To build = tubes=20 that could serve as blood vessels, for instance, they lay down = successive rings=20 containing muscle and endothelial cells, which line our arteries and = veins. "We=20 can print any desired structure, in principle," Forgacs told the = meeting.

Other tissue engineers have tried printing 3D structures, using = modified=20 ink-jet printers which spray cells suspended in liquid (New = Scientist, 25=20 January 2003, p 16). Now Forgacs and a company called Sciperio have = developed a=20 device with printing heads that extrude clumps of cells mechanically so = that=20 they emerge one by one from a micropipette. This results in a higher = density of=20 cells in the final printed structure, meaning that an authentic tissue = structure=20 can be created faster.

Cells seem to survive the printing process well. When layers of = chicken heart=20 cells were printed they quickly begin behaving as they would in a real = organ.=20 "After 19 hours or so, the whole structure starts to beat in a = synchronous=20 manner," says Forgacs.

Most tissue engineers trying to build 3D structures start with a = scaffold of=20 the desired shape, which they seed with cells and grow for weeks in the = lab.=20 This is how Anthony Atala of Wake Forest University in Winston-Salem, = North=20 Carolina, and his colleagues grew the bladders which he successfully = implanted=20 into seven people (New Scientist, 8 April 2006, p 10). But if = tissue=20 engineering goes mainstream, faster and cheaper methods will be a boon.=20 "Bioprinting is the way to go," says Vladimir Mironov, a tissue engineer = at the=20 Medical University of South Carolina in Charleston.

From issue 2547 of New = Scientist=20 magazine, 13 April 2006, page 19

Printed on Fri Jan 19 19:10:33 GMT = 2007