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Making a bit of me : A machine that prints organs is coming to market By The Economist
Illustration
by David Simonds
Economist: Making body parts
The great hope of transplant surgeons is that they will, one day, be able
to order replacement body parts on demand. At the moment, a patient may wait
months, sometimes years, for an organ from a suitable donor. During that
time his condition may worsen. He may even die. The ability to make organs
as they are needed would not only relieve suffering but also save lives. And
that possibility may be closer with the arrival of the first commercial 3D
bio-printer for manufacturing human tissue and organs.
The new machine, which costs around $200,000, has been developed by
Organovo, a company in San Diego that specializes in regenerative medicine,
and Invetech, an engineering and automation firm in Melbourne, Australia.
One of Organovo’s founders, Gabor Forgacs of the University of Missouri,
developed the prototype on which the new 3D bio-printer is based. The first
production models will soon be delivered to research groups which, like Dr
Forgacs’s, are studying ways to produce tissue and organs for repair and
replacement. At present much of this work is done by hand or by adapting
existing instruments and devices.
To start with, only simple tissues, such as skin, muscle and short
stretches of blood vessels, will be made, says Keith Murphy, Organovo’s
chief executive, and these will be for research purposes. Mr Murphy says,
however, that the company expects that within five years, once clinical
trials are complete, the printers will produce blood vessels for use as
grafts in bypass surgery. With more research it should be possible to
produce bigger, more complex body parts. Because the machines have the
ability to make branched tubes, the technology could, for example, be used
to create the networks of blood vessels needed to sustain larger printed
organs, like kidneys, livers and hearts.
Printing history
Organovo’s 3D bio-printer works in a similar way to some
rapid-prototyping machines used in industry to make parts and mechanically
functioning models. These work like inkjet printers, but with a third
dimension. Such printers deposit droplets of polymer which fuse together to
form a structure. With each pass of the printing heads, the base on which
the object is being made moves down a notch. In this way, little by little,
the object takes shape. Voids in the structure and complex shapes are
supported by printing a “scaffold” of water-soluble material. Once the
object is complete, the scaffold is washed away.
Researchers have found that something similar can be done with biological
materials. When small clusters of cells are placed next to each other they
flow together, fuse and organise themselves. Various techniques are being
explored to condition the cells to mature into functioning body parts—for
example, “exercising” incipient muscles using small machines.
Though printing organs is new, growing them from scratch on scaffolds has
already been done successfully. In 2006 Anthony Atala and his colleagues at
the Wake Forest Institute for Regenerative Medicine in North Carolina made
new bladders for seven patients. These are still working.
Dr Atala’s process starts by taking a tiny sample of tissue from the
patient’s own bladder (so that the organ that is grown from it will not be
rejected by his immune system). From this he extracts precursor cells that
can go on to form the muscle on the outside of the bladder and the
specialised cells within it. When more of these cells have been cultured in
the laboratory, they are painted onto a biodegradable bladder-shaped
scaffold which is warmed to body temperature. The cells then mature and
multiply. Six to eight weeks later, the bladder is ready to be put into the
patient.
The advantage of using a bioprinter is that it eliminates the need for a
scaffold, so Dr Atala, too, is experimenting with inkjet technology. The
Organovo machine uses stem cells extracted from adult bone marrow and fat as
the precursors. These cells can be coaxed into differentiating into many
other types of cells by the application of appropriate growth factors. The
cells are formed into droplets 100-500 microns in diameter and containing
10,000-30,000 cells each. The droplets retain their shape well and pass
easily through the inkjet printing process.
A second printing head is used to deposit scaffolding—a sugar-based
hydrogel. This does not interfere with the cells or stick to them. Once the
printing is complete, the structure is left for a day or two, to allow the
droplets to fuse together. For tubular structures, such as blood vessels,
the hydrogel is printed in the centre and around the outside of the ring of
each cross-section before the cells are added. When the part has matured,
the hydrogel is peeled away from the outside and pulled from the centre like
a piece of string.
The bio-printers are also capable of using other types of cells and
support materials. They could be employed, Mr Murphy suggests, to place
liver cells on a pre-built, liver-shaped scaffold or to form layers of
lining and connective tissue that would grow into a tooth. The printer fits
inside a standard laboratory biosafety cabinet, for sterile operation.
Invetech has developed a laser-based calibration system to ensure that both
print heads deposit their materials accurately, and a computer-graphics
system allows cross-sections of body parts to be designed.
Some researchers think machines like this may one day be capable of
printing tissues and organs directly into the body. Indeed, Dr Atala is
working on one that would scan the contours of the part of a body where a
skin graft was needed and then print skin onto it. As for bigger body parts,
Dr Forgacs thinks they may take many different forms, at least initially. A
man-made biological substitute for a kidney, for instance, need not look
like a real one or contain all its features in order to clean waste products
from the bloodstream. Those waiting for transplants are unlikely to worry
too much about what replacement body parts look like, so long as they work
and make them better.
Economist: Making body parts
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An individualized 3D printed product offers better comfort (or value) to
the customer and will sweep away established mass produced variants. But,
what I want to make clear is that this is not some future scenario that
might happen in ten years. The hearing aid industry has already been
transformed by 3D printing. Market share has shifted, manufacturers have
been displaced and the industry has been turned on its head. If you
are in any kind of manufacturing business then its nice that 3D printing is
now being discussed round the water cooler but you really should be talking
about it in the board room. At the very least this technology will
accelerate your product development. But, depending on your business you may
be Motorola cheerfully pressing ahead with analog while everyone else goes
digital. 
Right side is an image of a build tray of an
There is a much bigger chance that you have a dental implant that is 3D
printed. Phil Reeves rough estimates that there have been anywhere
from 500,000 to 750,000 3D printed dental implants in patients worldwide.
Crowns, bridges & caps are 3D printed with several methods. On the right is a build
platform of a 