Researchers are working their way closer to a grail of tissue engineering: a fabricator that can print out living organs in three dimensions just like the rapid prototyping devices used today in a variety of industries. Plastics and inks become cells and biomaterials, and the whole works much the same way. Organs are many magnitudes more complex in structure than the plastic prototypes turned out by fabricators in the design industry, but the cells used to build those organs can - in theory - be induced to do most of the small-scale organization for you. Roland Piquepaille notes one of the latest technology demonstrations:
"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.'"
Researchers are still building the components of organs in the technology demonstrations - we're a few years away from fabrication of even "simple" organs, such as the heart or liver. As I've noted previously, the big hurdle of the moment is getting the blood vessels - the vasculature - right. Blood transport is vital to building living tissue of any meaningful size, and it's a hard problem if all the blood vessels, from microscopic capillary networks on up, have to be designed by hand into the tissue you're printing.