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Stories:
Imitation of Life
Imitation of Life
Developed by engineers at the Massachusetts Institute of Technology in the 1990s, "three-dimensional printing" has become an important tool for quickly fabricating physical models from computer data. More recently, a group of MU researchers have begun using the process to envision the previously unimaginable: "printed" human body parts.
As a concept, 3-D printing can be tough to visualize. But the process itself is remarkably straightforward. First, researchers use a computer program to create a "layered" digital model of the object to be replicated. This is downloaded to the 3-D printer which then, according to the MIT Laboratory for Manufacturing and Productivity, lays down "a thin distribution of powder spread over the surface of a powder bed. Using a technology similar to ink-jet printing, a binder material selectively joins particles where the object is to be formed."
Next, a piston in the printer lowers the finished layer so that the next one can also be spread and joined. The process is repeated until the object is complete.
Given the right set of instructions, 3-D printing machines can model any object imaginable, from prototypes of engine parts to tiny facsimiles of gothic cathedrals. "But why stop there?" asks Gabor Forgacs, a biological physicist at MU.
He is currently at work perfecting a form of three-dimensional printing for use with physiological components. It's an effort that could conceivably help the human body replicate vital organs. Already Forgacs and his research team have discovered that, with a little help from their own 3-D printing device, human cells can assemble themselves into tubes and parts of organs. Key to the process is "bio-ink," spherical drops of cellular gel developed by Forgacs which, when loaded into his special 3-D printer, can create perfect copies of ring-shaped cell patterns. These cellular rings can then be mechanically stacked one atop the other in a manner similar to the MIT process. Later, they fuse to become biological tubes.
"A large part of the body is made of tubes," Forgacs says. "We can now make 3-D hollow biological tubes and organ modules, which potentially could be used as grafts, or for doing research on a particular drug using an organ substitute. … The next step is the construction of functional organ modules, prepared outside of the living organism and then implanted into the organism."
That is, admittedly, a big step. But it's an exciting one. Unlike human organs currently available for transplant, there is little chance the body will reject an organ constructed from its own cells. Forgacs finding also implies that scientists may not need complete blueprints to build replacement organs — "printing" organs would mean that self-assembling cells could do the heavy lifting. "This study suggests you have to provide the proper environment and place the cell aggregates in the correct geometrical shape," he says. "After that, the biological system takes over and completes the structure."
Forgacs says he is currently working to obtain a patent for bio-ink, as well as seeking further funding for his research. His findings were published in the March 2 edition of the Proceedings of the National Academy of Sciences.
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