Every year, pharmaceutical companies invest many millions of dollars to test drugs that will never reach market while the number of patients waiting for organ transplants continues to increase. Would it be possible to create human tissues to help to solve both problems? A research team from the University of Missouri in Columbia (MU) thinks so. According to Nature, the researchers have created functional blood vessels and cardiac tissue, using a 'printer' that dispenses cells instead of ink. This has been done before with the help of 'scaffolds.' But this team didn't use them. Instead, it was able to print various structures from scratch. This might be a brilliant and promising step towards printing organs on demand. But read more...
You can see above how this novel technology works: "(a) A patent pending device (schematic) cuts the earlier prepared tissue/cellular slurry into cylindrical aggregates. (b) The spheroidal bio-ink particles result from the rapid rounding of the tissue/cellular cylinders upon incubation (the one shown is of 500 mm and is made of CHO cells fluorescently labeled with a membrane dye). (c) The printer cartridge is a micropipette housing the spherical multicellular aggregates. (d) The printer. The one shown has been designed and built by nScrypt (Orlando, FL). (e) Spheroids are delivered one by one into the hydrogel according to a computer script encoding the printable shape. (f) The outcome of the printing process is a set of discrete spheroids, here 500 mm aggregates of CHO cells, fluorescently labeled with red or green membrane dyes." (Credit: Forgacs lab, MU)
This research work has been led by Gabor Forgacs, Professor of Physics at MU and his colleagues of his lab at MU. For more information, you can read the pages about the BioPrinter they've used and about the research done there about bioprinting.
The research team has also developed a website about Organ Printing. On the Facilities page, you'll see a picture of the bio-printer, a product developed by nScrypt, Inc., a company based in Orlando, Florida. Here is a link to their tissue engineering tools.
Here is a quote from Forgacs about the future. "'We will never be able to print a liver with all of its many details,' says Forgacs. 'But it is not necessary. If you initiate the process, nature will do it for you.'"
According to MU, "the team used bio-ink particles, or spheres containing 10,000 to 40,000 cells, and assembled, or 'printed,' them on to sheets of organic, cell friendly 'bio-paper.' Once printed, the spheres began to fuse in the bio-paper into one structure." Nature adds that "when they printed out cardiac and endothelial cells, the cells fused into a tissue after 70 hours, and began beating in time like regular heart tissue after 90 hours."
Nature also explains why this project is different from previous ones. "What makes this work different from that done in most other tissue-engineering labs is that Forgacs's team does everything without a scaffold -- they don't start with an object shaped like the tissue or organ they are aiming to create, but instead plan to print the whole thing from scratch, from the vasculature up. This should make it easier to print any type of organ, they say, as they don't have to develop different scaffolds for each tissue type. 'Often when you implant a scaffold you get inflammation,' says Forgacs."
And here is how works the nScrypt printer used by Forgacs and his colleagues. "The printer has three heads, each of which is controlled by an attached computer, that can lay down spheroids of cells much as a desk printer would lay down ink. Two of the heads print out tissue cells (mixtures including, for example, cardiac and endothelial cells), while the third prints a 'gap-filler' (such as collagen) that fills a space temporarily until the other cells have fused. So to make a blood vessel, for example, lines of cells are laid down with lines of collagen in the middle, which will later be extracted to make way for blood."
This research work has been published in Tissue Engineering, a scientific journal of the Mary Ann Liebert, Inc. group under the title "Tissue Engineering by Self-Assembly of Cells Printed into Topologically Defined Structures" (Tissue Engineering Part A, Volume 14, Number 3, Pages 413-421, March 1, 2008) and is freely available. Here are two links to the abstract and to the full paper (PDF format, 10 pages, 496 KB) the figure above has been extracted from this article.
Finally, here are three more links related to this research effort.
- Organovo, Inc. is "a seed-stage regenerative medicine company" funded by Forgacs to bring such developments to market.
- MU Research Team Makes Progress Toward 'Printing' Organs (University of Missouri-Columbia news release, November 5, 2007)
- Research team makes progress toward 'printing' organs (MU College of Arts and Science Research Communication Project, November 2007)
Sources: Emma Marris, Nature, March 20, 2008; and various websites
You'll find related stories by following the links below.