Could Bioprinting Replace the Need for Organ Donors?

3D printing, an already relatively commonplace technology, has diverse manufacturing applications and has influenced numerous industries, impacting everything from construction and architecture to fashion, design, and even space travel. Recently, the scope of 3D printing has extended even further to include the printing of biological materials.

3D Bioprinting 101

3D bioprinting is a fascinating technology with vastly diverse potential applications. The concept of 3D bioprinting is based closely on that of a “traditional” 3D printer. However, where 3D printers produce materials such as plastics, ceramics or metals, a bioprinter can deliver layers of biomaterial, including living cells, that actually function as they would inside a body. The concept of printing living cells to produce artificial tissues and organs sounds like something from a 1980s sci-fi novel and can be difficult to wrap your head around, so here’s some background into how the process works.

The Secret Ingredient: Bio-Ink

Like any printing process, a bioprinter requires ink. However, cyan and magenta aren’t quite going to cut it when it comes to bioprinting – a highly specialized substance known as “bio-ink” is required. Bio-ink is predominantly composed of living cells, but also often includes additional materials to make the cells feel right at home, like a biopolymer hydrogel that acts as a 3D molecular scaffold for the cells to attach to. This allows the cells to spread and proliferate, and also provides them with some protection during the printing process.

Depending on what is being printed, a specific cell type is required. If you want to print part of a liver, you need liver cells. If you want to print some skin, you need skin cells. Plus, if you want to use these manufactured tissues to treat a patient, it’s best to start with cells from that same patient. In the same way that a family member is usually the best option for being an organ donor, having cells that are genetically similar to the host they will be used for increases the chances of a successful transplant.

Sometimes, the cells don’t proliferate to a high enough number to facilitate the printing. When this occurs, stem cells from the patient can sometimes be used – they have the ability to differentiate into your cell type of choice under the right conditions.

Once you’ve chosen your cell type and grown them up, and manufactured a bio-ink that provides the scaffolding and 3D structure your cells require, they can be printed using a device not too dissimilar to a regular office printer, which uses a 3D model of the structure you are trying to create and injects the cells into the appropriate 3D arrangement through a syringe. It’s that simple. Well, sort of.

Did Someone Leave Their Pancreas on the Printer?

Many people with type two diabetes wait in vein for a pancreas transplant for years, trying to manage their condition with insulin and dietary control. In 2019, a group of Polish researchers printed the world’s first artificial pancreas, complete with blood vessels to assist in the transplantation process and ensure that the organ can receive nutrients and oxygen once inside its new host.

To create the pancreas, pancreatic cells from animals were combined with a biopolymer and then printed through a syringe, in accordance with a previously developed 3D model. At the same time, with a second syringe, blood vessels were printed to be incorporated into the organ. The bio-ink, liquid in the syringe, set and formed solid layers once printed.

Experiments on pigs and mice are currently ongoing and if the results are promising, the research will shift to using human cells to create the pancreas. Lead researcher and transplant surgeon Dr Michal Wszola believes that the first bioprinted pancreas could be transplanted into a human patient within 3-5 years; a bold suggestion that could have staggeringly positive implications for diabetes patients worldwide.

What Does the Future Hold for Bioprinting?

Many researchers (and subsequently investors) across the globe are seeing the potential that bioprinting has, with substantial grant funding now being dedicated to research in this field. In 2018, a group at the Indiana University School of Medicine received a $9 million funding boost to further develop their ongoing research on organ bioprinting for transplants, and several collaborations have been formed between 3D printing companies and biomedical corporations to further develop the technology behind bioprinting.

While the printing of certain organs such as lungs and bladders is becoming relatively straightforward, more complex organs with a variety of cell types (such as the brain), or with intricate physical design (such as the heart) pose a different set of challenges. What’s more, ensuring that these organs can function inside a donor, and be integrated into the donor’s circulatory and immune systems, largely remains to be seen.