A new biopaper for organ printing
Organ printing is an emerging branch of medicine which uses healthy cells to repair a damaged or diseased organ. But as its name implies, this new medical technology needs ink, paper and a printer. Now, a new hydrogel -- or biopaper -- developed at the University of Utah has been selected by the National Science Foundation (NSF) to speed up this process, according to Deseret Morning News. This five-year NSF study will initially try to print blood vessels and cardiovascular networks. But its real goal is to build some complex organs, such as livers or kidneys. This technology can potentially help millions of people waiting for transplants.
So what's new with this hydrogel?
"Think of taking a blood vessel -- a cylindrical object -- and trying to reconstruct it in 3D with two-dimensional slices," said U. Presidential Professor of Medicinal Chemistry Glenn D. Prestwich, who created the hydrogel. He likens the resulting slices to a "non-nutritious doughnut" with muscle cells on the outside and endothelial cells inside.
To make the cylinder, those flat doughnut sections are literally printed, one thin layer of cells and hydrogel at a time, the platform moving away from the printer's "bio-ink"-delivering needles as the cylinder grows.
Below is a diagram showing the "schematics of building a tubular organ module by bioprinting. The blue sheets represent the biopaper or scaffold gel. The gel and the histotypical spherical bioink particles are deposited/printed layer-by-layer." (Credit: Gabor Forgacs, University of Missouri-Columbia, in this news release from the University of Utah).
Here are more details about this hydrogel.
[It] is made of normal biological material from the body, two sugar chains that, mixed with a reactive substance, turn from liquid into gel. It's the type of biologic filler that is used in ophthalmic surgery, in injections in knee joints to ease pain or in the face to erase tiny wrinkles.
"We've put a chemical handle on it, sort of like Velcro, to make something cells like and will attach to. The cells eat it up, then secrete a new tissue matrix that's needed for the tissue to function. And those become part of the final product."
Buts is this real? Will this help people in need for transplants?
The NSF study will try first to print blood vessels and cardiovascular networks. Once they prove it can be done, the scientists will look at more complex organs such as livers and kidneys and simpler but more mechanical organs like the esophagus, Prestwich said.
Experts believe that millions of people who need transplants eventually will benefit from organ printing. "I believe in five years we're going to be able to print simple organs, such as a cardiovascular network or a urethra," Prestwich said.
For this NSF study, Prestwich is working with Gabor Forgacs, from the University of Missouri-Columbia, who is a pioneer in organ printing.
Forgacs said he uses Prestwich's hydrogel because of its biocompatibility with other cells. Instead of disappearing, it becomes part of a matrix that is integral to the tissue.
For more information about the research projects of the two professors mentioned above, you can visit the Prestwich Research Group home page or the Organ Printing project page at the University of Missouri.
And don't miss this paper, Organ printing: Fiction or science (PDF format, 5 pages, 160 KB), which contains more details about bioinks and biopapers.
Finally, you might want to read a previous post about a new use for old printers: treating burn victims.
Sources: Lois M. Collins, Deseret Morning News, Salt Lake City, November 5, 2005; and various web sites
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