How do 3D Printed Organs Work?

Here are some examples of 3D printed organs. Notice the really tiny heart; this is the type of organ the researchers from Tel Aviv University created. From 3dnatives.com 

According to the American Transplant foundation, in the United States, 114,000 people are on a waiting list for an organ that could save their life. Additionally, 20 people die every day because they did not receive the organ they needed. So doctors and engineers have teamed up and started developing 3D-printed organs. 3D-printed organs combat the fear of rejection in which the patient’s body attacks the implanted organ or tissue because it sees it as a foreign object. This is because they are made from the patient's own cells. Also, they would make organs transplants readily available for all people who are suffering from organ failure, and who need tissue replacements.

This is an image of the 3D printed heart being made. From Interested Engineering

You might be asking, how does this work? Doctors and engineers are not using the typical 3D printers that you would find in an engineering classroom, where plastic or wax is usually used for printing; their printers use a mix between patient cells and biodegradable plastic to print the organs. There are multiple projects going on around the world, and there have been countless advances in recent years. Industry leader Dr. Anthony Atala of Wake Forest University outlines the process he and his team use in his talk to Singularity University (not a real University, it is similar to TED where they provide free educational content). First, a “scaffold” is created with a 3D printer as a base for the human cells to be placed on so they grow in the right shape and form of the organ. This is created with a biochemical plastic which dissolves into the body in the same way that some stitches do. Then tissue is taken from the patient, which, as Dr. Atala states, is about half the size of a postage stamp. The cells from this are then expanded outside the body, they replicate until then a few weeks later there are enough cells to use. Next, they take the scaffold and coat the inside with lining cells and the outside with muscle cells. Then it is placed in an incubator so the cells can multiply and grow. After a few more weeks, the organ is fully grown, and theoretically can be put into a human.

While all of this sounds great, there are flaws. Doctors and engineers are not far enough into their research to make these organs a possibility right now. Dr. Anthony Atala has had success with more simple organs, such as bladders, ears, and wind pipes. These are successful because they do not carry out complex functions of a heart or a kidney. A heart needs to carry out the necessary function of pumping blood, and while doctors are trying to make that a reality, according to the Washington Post, they have not figured out a way to make it pump as a human heart needs to. Researchers from Tel Aviv University 3D printed a heart by removing cells and biomaterials from a patient. These were then taken and separated, and these cells were reprogrammed to become stem cells, which then differentiated into cardiac cells and blood vessel cells. All of these materials are placed in a 3D printer and a 3D printed heart is created. While this is an advancement from previous works, the heart is the size of a strawberry, and it cannot pump blood; so it is far from being placed in humans. Furthermore, organs such as kidneys and hearts are full of tissue that carries out the processes of the organ, which makes it harder to print these versus more simple organs such as a bladder. 

Doctors are still learning about how to create larger, more complex organs. According to CBS doctors are, however, having some success with printing heart patches to repair a heart that was damaged due to heart attack, and while it will help greatly, it is not widely available. This is the other issue with 3D printing technology: because it is still in its early developmental years, people do not have access to it in the way that many of these doctors wanted. Once it is fully developed, it will be more accessible than the current transplant options, because it would cost roughly 3% of what transplants cost now ($10,000 for a single bio-printer versus $330,000 for a kidney transplant). There is still a lot to learn about the uses of 3D printed organs; there needs to be more tests on humans, more advancements need to be made and their accessibility needs to be increased, but it is the future of medicine. It could help save those 114,000 people on the transplant list.