Straight from the Factory
Ultimately, any method for building new human organs will have to win approval from the U.S. Food and Drug Administration. And that means organ builders will need a standardized, reproducible manufacturing process, says MIT bioengineer Linda Griffith. To achieve that goal, Griffith and her colleagues have turned to a device invented by MIT engineer Emanuel Sachs and used for rapid prototyping and the manufacture of a variety of parts and tools: a three-dimensional powder printer, or 3DP machine.The machine builds up complex shapes layer by layer, based on a computer file capable of depicting the object as a series of horizontal slices. A roller pushes a thin layer of powder across a flat base plate resting on top of a piston. Next, an inkjet printer head distributes a glue, or binder, to solidify the powder only where the blueprint for that slice calls for solid material. The piston then ratchets the plate down by the thickness of the layer, and the process begins again. When all the layers have been printed, the new object can be removed from the machine, and the excess powder falls away.
By adapting the printer to use polymer powders, multiple print heads and special binders, Griffith and her collaborators created a tool capable of mass-producing polymer scaffolds for new tissues and organs. Not only does the printer allow the researchers to control a scaffold’s shape with great precision, it also allows them to build in chemical modifications to the structure’s surface that help tell different types of cells exactly where and how they should grow.
It’s just that sort of fine control that may help tissue engineers conquer even the most complicated organs. Indeed, Griffith is now-along with Vacanti and Princeton, NJ-based Therics-working out ways to manufacture livers and other organs with three-dimensional printing. Griffith already knows a great deal about growing liver tissue; she worked on the details while leading an effort to develop a liver-cell-based biological-weapon detector for the U.S. Defense Advanced Research Projects Agency. The hope is that scientific knowledge, combined with three-dimensional-printing technology, will make building a liver for implantation possible.
If everything pans out as Griffith, Vacanti and their colleagues hope, manufacturing machines could someday hum in FDA-certified organ factories. It’s too soon to know if those factories will churn out entire organs on site, or if they’ll instead produce and ship elaborate scaffold structures on which doctors will grow patients’ own cells, right in the hospital. But either approach, if successful, promises one thing: an end to transplant waiting lists.