SAN DIEGO -– Say goodbye to donor lists and organ shortages. A biotech firm has created a printer that prints veins using a patients’ own cells. The device could potentially create whole organs in the future.

"Right now we're really good at printing blood vessels,” says Ben Shepherd, senior research scientist at regenerative-medicine company Organovo. “We printed 10 this week. We're still learning how to best condition them to be good, strong blood vessels."

Most organs in the body are filled with veins, so the ability to print vascular tissue is a critical building block for complete organs. The printed veins are about to start testing in animal trials, and eventually go through human clinical trials. If all goes well, in a few years you may be able to replace a vein that has deteriorated (due to frequent injections of chemo treatment, for example) with custom-printed tissue grown from your own cells.

The barriers to full-organ printing are not just technological. The first organ-printing machine will cost hundreds of millions of dollars to develop, test, produce and market. Not to mention the difficulty any company will have getting FDA approval.

"If Organovo will be able to raise enough money this company has [the] potential to succeed as [the] first bioprinting company but only time will show," says Dr. Vladimir Mironov, director of advanced tissue biofabrication at the Medical University of South Carolina.

Organovo walked Wired.com through the process it uses to print blood vessels on the custom bioprinter.

Above:

Bioreactor ———-

Shepherd places a bioreactor inside an incubator where it will be pumped with a growth medium for a few days. The bioreactor uses a special mixture of chemicals that are similar to what cells would see when they grow inside the body, which will help the cells become strong vascular tissue.

Photos: Dave Bullock/Wired.com

Stem Cells ———-

Senior research scientist Ben Shepherd removes stem cells from a bath of liquid nitrogen. The cells will be cultured to greatly increase their number before being loaded into the printer. Eventually these cells could be taken from a variety of places in a patient's body –- fat, bone marrow and skin cells –- and made into a working vein.

After the cells are defrosted they are cultured in a growth medium (above). This allows the cells to multiply and grow so they can be used to form veins. The medium also uses special chemicals to tell the stem cells to grow into the cell type required, in this case blood-vessel cells. Once a enough cells are produced, they are separated from the growth medium using a centrifuge (below) and compressed into pellets.

Photos: Dave Bullock/Wired.com

Hydrogel Scaffolding ——————–

The first step of the printing process is to lay down a material called hydrogel, which is used as a temporary scaffolding to support the vein tissue.

The custom-made printer uses two pump heads that squirt out either the scaffolding structure or the cells into a petri dish. The pump heads are mounted on a precision robotic assembly for microscopic accuracy. The head on the right is dipping into the container of hydorogel in the photo above.

A chamber called a bioreactor is used to stimulate the vein. It's prepared before the vein is printed. The bioreactor is a fairly standard piece of biotech machinery. It is machined out of a block of aluminum that surrounds a plastic container with various ports. These ports are used to pump in chemicals that will feed the growing vein.

Before printing the veins, tubes of the cultured cells are loaded into the print head manually, like a biomass print cartridge.

Photos: Dave Bullock/Wired.com

Hydrogel Mold for Blood Vessels ——————————-

Lines of the hydrogel are laid down in parallel in a trough shape on the petri dish. Then cylinders of cell pellets are printed into the trough.

One more cylinder of hydrogel is printed into the middle of the cells, which serves to create the hole inside the vein where blood will eventually flow (below).

Photo: Dave Bullock/Wired.com

Illustration courtesy Organovo

Growing Into Veins ——————

The printed veins are then left in a different growth medium for several weeks. The cells soon release from the hydrogel, and a hollow tube of vascular cells is left behind.

Photo: Dave Bullock/Wired.com

Happy Veins ———–

The printed cells in tubular form are then placed into the bioreactor. The bioreactor (above) pumps a special cocktail of proteins, buffers and various other chemicals (below) through the printed vein. This conditions the cells to be good, strong veins and keep them happy.

Photos: Dave Bullock/Wired.com

Finished Product —————-

After their stay in the bioreactor, the pellets of cells grow together to form veins which can then be implanted in the patient. Because the veins are grown from the patient's own cells, their body is more likely to accept the implanted vein.

Photo: Organovo