Artificial Organs? How We Can Get There with 3D Printing

Medical technology is rapidly advancing, with new technologies emerging faster than we can appreciate. Technologies such as liquid biopsies, 3D fluorescence imaging, and heart-in-a-box are just a sampling of the very cool advances we’ve seen in medicine in the past decade. Liquid biopsies can detect cancer in a patient’s blood, giving clinicians a reliable, non-invasive, and informative clinical tool to use to monitor cancer growth over time. Three dimensional imaging makes it easier to see what’s going on in your tissues. And heart-in-a-box allows donor hearts to live longer before transplanting them, giving time for hearts to travel far distances to patients in need. But, a tool that’s not so new yet is still particularly fascinating in its potential medical applications is the 3D printer.

What is 3D printing?

3D printing describes a process that fuses or deposits materials to produce a 3D object, one layer at a time. These materials can be anything from liquids, powders, and ceramics to plastics, or even living cells. The 3D printer works by following a computer file that builds the object’s foundation first, and then layers the materials on top to form almost any shape. 

The Origins of 3D printing

Charles Hull, a physics engineer, developed three-dimensional printing in 1984. He originally named his invention ‘stereolithography,’ and it allowed designers to create 3D objects using only computer code. He created his machine to build plastic objects using a type of acrylic material that, when exposed to UV light, instantly turns solid and can mold to your design. Later on, designers started using powders and other materials, opening up the potential of what could be 3D printed. 

The technology is mainly used in manufacturing. Commercially, manufacturers use 3D printers to build prototypes, models, and molds of potential products. Many companies use 3D printing to create products and parts, such as shoe cleats, jewelry, car parts, bridge prototypes, and construction equipment, with companies like Nike, Volvo, and more benefiting from this new efficient manufacturing method. The 3D printer has already revolutionized the manufacturing industry, but its potential for medical applications is rising.

By 1999, the first 3D printed organ was implanted into a human. Scientists from the Wake Forest Institute for Regenerative Medicine used synthetic building blocks to create a scaffold of a human bladder, and then coated it with a human bladder cells, which multiplied to create a new bladder. Plus, by using cells taken from the same patient,  they avoided rejection, like you see with traditional organ transplants. In the early 2000s, engineers at Clemson University started modifying ink-jet printers to dispense biomaterials. From there, the medical applications of 3D printing grew exponentially.

A 3D printed bladder mold coated with human bladder cells resting in a mixture of nutrients and growth factors. 

Today, the medical applications of 3D printing are vast and wide-reaching. An interesting feature of 3D printing is that it gives us the ability to customize and personalize medical equipment. It’s incredibly beneficial to produce custom prosthetics and implants. These custom-made implants, prostheses, and even surgical tools can reduce surgery time, recovery, and overall surgical success (not to mention the significant reduction in costs). So far, most medical uses for 3D printing are not cost-effective on a large scale, but it’s proving cost-effective for small, complex, and customized products. For children, who grow out of their prostheses rather quickly, 3D-printed prostheses significantly help lower medical costs because the cost to print new ones is cheaper than traditional methods. In addition, the lower cost of these prostheses makes them more accessible to individuals and communities of lower income countries.

Other commercial medical products include hearing aids, stethoscopes, and items used in dentistry, such as crowns, bridges, plaster models, and surgical guides. 3D printed models of surgical tissue sites significantly improves the ability of medical teams to plan for surgeries. Doctors can use different scanned images of a patient (by MRI, CT, or X-ray), convert them into 3d printable files, print out a model of the tissue they’re performing surgery on, and practice the procedure beforehand. Medical schools are using these same methods and tools to teach young healthcare professionals.

What it may look like to 3D print a human heart one day.

3d printing also can help reduce the shortage of donated tissue and organs. On average, 20 people die everyday that were in need of an organ transplant. Right now, there are more than 113,000 people in need of an organ transplant, and only 3 in 1000 people die in a way that allows for organ transplantation. For example, if someone dies with cancer or an infection in their body, their organs cannot be transplanted. This area is where scientists see the most value with bioprinting. 

3D printed ear cartilage for an infant.

Tissue engineers have taken steps toward that goal. From Cornell engineers to Louisville scientists and many researchers in between, scientists have now printed functional liver cells, cartilage, heart valves, and artificial ears. While the first 3D-printed bladder transplant was in 1999, and we’ve seen a few other notable cases since, including a life-saving kidney transplant from an adult to a child and a face transplant for a man surviving cancer, 3D-printing functional organs for transplantation is generally beyond reach. The main challenges are keeping the organs alive long enough to use and the need to test for safety in humans. Hopefully, with more research and innovation, in the next 10-20 years as bioprinting improves, that will change. 

The economics of 3D printing
Standard 3D printing machine. Costs $599 on Toolots.

3D printing is growing near a $3 billion industry. In 2014, only $11 million of that industry was invested in medical applications. However, costs toward medical applications in 3D printing are expected to grow to 21% in the next 10 years ($1.9 billion out of an $8.9 billion industry). In 2008, a 3D printer cost about $15,000. Now, consumers are able to purchase a 3D printer for just $300-1000 and download the software for designing objects. Its accessibility is allowing many people to build clothes, car parts, and even jewelry. One of the first and largest companies that produce 3D-printed living human tissue is Organovo. By 2014, they were able to create a human liver, but it only lasted 40 days. Organovo has now printed (at least partially) human kidneys, bone, cartilage, muscle, blood vessels and lung tissue, but it’s main revenue driver is bio-printed liver tissue for studying the toxicity new medications.  (Disclaimer: This article is not an endorsement of Organovo.  Neither the author nor the Illinois Science Council has received any form of compensation from Organovo in relation to this article.)

While 3D printing has revolutionized the manufacturing industry, it has only made a dent in commercial medicine. However, bioprinting is an important invention that will continue to revolutionize medicine as well as manufacturing methods. Its applications are ever-growing and the cost seems to come down year after year. Its potential to overcome the donor shortage could save thousands of lives each year. Overall, the future of medical applications using 3D printing is bright. Bioprinting applies to multiple sectors of medicine and all medical professionals should stay up to date on its progress. As far as the rest of us, keep watching the news for the next revolution in bioprinting because before you know it, we all might have printed materials within us!

References
  1. Ventola, Lee C., “Medical Applications for 3D Printing: Current and Projected Uses” Pharmacy and Therapeutics. 2014;39(10):704–11.
  2. Dodziuk, Helena. “Applications of 3D Printing in Healthcare.” Polish Journal of Cardio-Thoracic Surgery. 2016;3:283–93.

Terese Geraghty is a PhD candidate at Rush University Medical Center in Chicago, where she’s currently researching a new immunotherapy for the treatment of lung cancer. She’s passionate about seeing new technologies and medical innovation translated to the clinic. You can learn more about Terese on LinkedIn.