Above: Image © Godruma, istockphoto.com

Can you imagine being able to go shopping for new body parts? Or even being able to print them out? Thanks to 3D medical printing, that might one day be possible!

3D printers have improved a lot since they were first invented in 1983. Some of the most interesting advances have come from fusing engineering technology with medical technology. The result: a process that can 3D print human cells, tissue and even entire organs! This could change various medical procedures, including organ transplantation and even handling medical emergencies in space.

3D Printing: Star Trek vs. reality

In the Star Trek universe, machines called replicators made all sorts of handy objects such as food and uniforms. With some modifications, replicators could even create breathable air (oxygen and carbon dioxide) and human organs.

In the real world, 3D printers layer material on top of itself to create a 3D object. Typically, these printers use ink or nylon spools.

But 3D printing technology is also capable of printing living human tissue, mostly smaller and thinner tissues and sections of organs. In these cases, 3D printers use cells instead of ink or nylon spools. These cells are printed onto something called a scaffold, which gives the organ its approximate size and shape and gives the cells an attachment point. Without the scaffold, the printout would end up a giant pile of squishy cells!

Medical researchers and development teams can use these tissues for pharmaceutical drug testing. Eventually, scientists hope to use these printed tissues to patch areas of diseased organs.

Custom medical printing

One day, scientists hope to create fully functional 3D printed organs for transplant into human patients. It’s just a matter of when.

Right now, people needing organ transplants have to wait for appropriate donors. The body doesn’t always accept the transplant, so organ recipients sometimes need to take large amounts of immune-suppressing drugs to help their body accept the new transplant instead of fighting it off as a foreign body. But with 3D organ printers, scientists should be able to print 3D organs to match up exactly with the people who’ll get them!

Custom organs could even be manufactured to perform better than natural organs. For example, scientists have already created a prototype of an ear for people who have lost their sense of hearing. This ear is pretty realistic. Its outer shell is made up of gelatin-like substance called hydrogel. The ear also contains small silver particles to make it sensitive to sound, and cartilage to keep everything together.

Did you know? To make sure a transplanted 3D organ works, scientists need to hook it up properly. It’ll need a blood supply, neural inputs and (of course) be physically attached to the body itself!

Why aren’t scientists printing these organs already?

Cells need certain things to grow and divide: nutrients, a means to get rid of waste, and a specific temperature that can keep them alive. Usually, the body the cells live in and its many blood vessels provide all of these things.

3D printed organs have few, if any, blood vessels. And those vessels don’t actually have blood in them. In natural organs, blood vessels serve as channels, allowing water, nutrients and oxygen to permeate deeply into the tissue. Without blood vessels, supplying nutrients to and removing waste from a large mass of 3D cells is very difficult! That’s why most 3D medical printers can only create thin layers of tissue instead of more complex organ systems.

There’s another issue, too. Right now, 3D scanners can take an inanimate object like a cup, scan it into a file and send it to a printer. These scans can capture the outside of an object, but they can't reveal the inner workings of it.

This is a problem for 3D medical printing. Sophisticated medical imaging, like MRI, shows medical teams what an organ looks like, but it doesn't tell that team where the cells are. In order to create custom organs, medical teams need detailed blueprints for how to print organs with nerves, blood vessels, muscles and supporting tissues. Until that happens, scientists can’t use 3D printers for transplant medicine.

3D organs in space

Once scientists overcome some of these issues, 3D medical printing will be helpful in many situations - including space travels! Medical printers would be able to use cells to print organs, providing a potential emergency lifesaver for astronauts on missions.

It’s expensive to send operating room supplies, medical equipment and lifesaving machines into space. It’s also difficult to keep those supplies fresh, sterile and well-stocked. But keeping a small medical printer, the size of a toaster oven, on hand for emergencies is much cheaper, easier to maintain, and (pardon the pun) space-effective!

When will all this happen?

Hopefully one day, scientists will find a way to fully copy Star Trek replicator technology. Until then, you and I will have to settle for the science fiction version.

Did you know? 3D printers can create one thing that the Star Trek replicators could: 3D printed food!

Learn more!

The printed organs coming to a body near you (2015)
H. Ledford, Nature News

3D bioprinting of tissues and organs (2014)
S.V. Murphy & A. Atala, Nature Biotechnology 32

3D bioprinting of living tissues
Wyss Institute

Shakib Rahman

 Shakib Rahman is a coordinator with Let's Talk Science at the UofA.  He an avid soccer player and a sports nut in general.  He also has a a passion for science, science literature and TV. In his spare time, he writes science articles, some of which you can read here at CurioCity.

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