Headline Dec 21, 2014/



THE climax of   ''Sleeper'', a futuristic fantasy from the  1970s  that was directed and starred,  Woody Allen, has Mr Allen's character throw- 

The preserved,  disembodied nose of a  dictator  beneath a steamroller. 

In a movie filled with orgasmatrons and car-sized bananas, it is a last absurd gesture that vanquishes the villains.

If the film was made today, though, those villains would simply print another nose.

The idea of  printing organs has moved beyond the realm of fantasy, as the technology of  three-dimensional printing  has improved.

Though implantable organs are still beyond reach, researchers have used the technique to build layers of cells into living tissues.

And as several recent papers in  Science   by  Hagan Bayley, a chemical biologist at  Oxford University   -show, this approach is evolving fast. 

The first paper, published on 4th February, 2013, by Wenmiao Shu of Heriot-Watt University, in Edinburgh, described a machine gentle enough to print human embryonic stem cells in a distinct pattern.

Such cells are pluripotent, meaning they are able to become any type of cell in the body. That makes them valuable research tools.

They can, for example,  be turned into pure samples of human tissues on which to test drugs. It also means they might, in principle, be used to create artificial organs,

They are maddeningly delicate   -and thus difficult to print-  but Dr Shu and his colleagues have built printer that can overcome this using nozzles fitted with small valves gentle enough to stop the cells suffering undue stress as they move through them.

Tiny blasts of air push the cells onto a plate below, in regular spherical, globs and their pluripotency remains intact.

The second paper, published on February 20th, 2013,  in the Public Library of Science, showed how  3D  printing might help create artificial ears.

Lawrence Bonassar and Jason Spector of Cornell University scanned the ear of a five-year-old-girl. Using the image, they printed a mould. They then injected the mould with rat collagen, which acted as a scaffold, and millions of cartilage cells from calves.

After allowing the result to grow for a few days, they implanted it under the skin on a rat's back and left the cells to grow for three months. This produced a fair facsimile of an ear, the same size and shape as the original.

Dr Bayley's paper describes not living cells, but synthetic printed material made to act like them. A cell is, in essence, a drop of watery liquid surrounded by a fatty membrane.

Dr Bayley and his colleagues printed artificial versions of this arrangement : tiny droplets of an aqueous solution. each with a volume of a trillionth of a litre, were sprayed into oil in order to pick up a fatty coat.

On its own an individual droplet, even one with a fatty coating, is rather dull. Collectively, however, they become quite interesting. In one example, for example, Dr Bayley printed a pattern of droplets, some with proteins in their membranes.

Each droplet's coat bound to its neighbour's to create a wall made up of two layers. The proteins formed pores in these walls and when the researchers applied voltage, ions in the aqueous solution coursed through the pores, generating a signal similar to the  ''action potentials''  that carry messages through the nerve cells.

Until now, those who have thought about printing artificial organs have assumed that they would be made of real cells. Dr Bayley's approach offers an alternative: artificial organs made of artificial cells.

There would be an advantage to this, for such cells cannot reproduce and therefore could not become cancerous.

All of this work is in its early stages. No one is talking of transplantable artificial organs in the near future. But they may be only years, rather than decades, away.

''Science is an intellectual dead end,'' Mr Allen huffs near the end of  ''Sleeper''.

Drs Bayley, Bonnassar, Spector and Shu would no doubt beg to differ.

With respectful dedication to all the bioscientists in the world. See Ya all, Sirs, on !WOW!  -the World Students Society Computers-Internet-Wireless:

''' Mind Honours '''

'''Good Night and God Bless

SAM Daily Times - the Voice of the Voiceless


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