Can 3D-Printers really print a human organ?

In what would easily be the greatest accomplishment that the medical field will see, a belief that one day 3D-Printers will be able to construct live human organs for implantation. Dying patients could someday receive a 3D-printed organ made from their own cells rather than wait on long lists for the short supply of organ transplants. Such a futuristic dream remains far from reality, but university labs and private companies have already taken the first careful steps by using 3D-printing technology to build tiny chunks of organs. This action is being spearheaded by Tony Atala, director of the Wake Forest Institute of Regenerative Medicine in WInston-Salem, N.C. He says "Bioprinting organ for human uses won't happen anytime soon, but for tissues we've already implanted in patients — structures we've made by hand — we're now going back to those tissues and saying 'We know we can do better with3D printing.'"

Atala's group previously built lab-grown organs by creating artificial scaffolds in the shape of the desired organ and seeding the scaffold with living cells. They used the technique to grow artificial bladders first implanted in patients in 1999, but spent the last decade building 3D printers that can print both an artificial scaffold and living cells at the same time — a process that involves liquid "glue," which hardens into the consistency of gummy candy as it dries out.

Other labs think they can bypass the artificial scaffolds by harnessing living cells' tendencies to self-organize. That avoids the challenge of choosing scaffold material that can eventually dissolve without affecting the living cells, but leaves the initial structure of living cells in a delicate position without the supporting scaffold.

"If you do what we do with putting cells in the right place, you don't start with anything structural to hold things up," said Keith Murphy, chairman and CEO of Organovo, a startup San Diego-based company "For us, the challenge is the strength and integrity of the structure."

Organovo scientists have experimented with building tiny slices of livers by first creating "building blocks" with the necessary cells. The company's 3D printers can then situate the building blocks in layers that allow the living cells to start growing together.

Stem cells taken from a patient's fat or bone marrow can provide the 3D-printing material for making an organ that the body won't reject, Murphy said. His company worked with Stuart Williams, executive and scientific director of the Cardiovascular Innovation Institute in Louisville, Ky., on extracting the stem cells from fat.

"http://www.makerbot.com/blog/2011/03/08/3d-printing-an-organ-live-onstage-at-ted/"