22.07.2024
Bioprinting - a fascinating technology that blurs the boundaries between biology and technology - has attracted a lot of attention in recent years. The process combines the principles of 3D printing with biological materials to produce complex tissue structures. Bioprinting opens up new avenues in medical development as well as transplantation and drug research. But how does bioprinting work and where do we stand today? Find out the answer in the following interview with Dr. Harald Unterweger, Project Manager in the Health Innovation Network of Bayern Innovativ GmbH.
Harald, are bioprinting or organs from the 3D printer already a reality or still a dream of the future?
Dr. Harald Unterweger: The vision of organs from the printer is not so far-fetched. A lot of things are being printed at the moment, such as steaks and houses. So why not organs too?
The technology is actually relatively old. The first beginnings were made 20 years ago. Back then, a 3D-printed bladder was colonized with cells and implanted in a patient who is still alive today. However, more complex structures can already be printed and transplanted, e.g. bone or cartilage material. A few weeks ago, for example, it was reported that a boy from Salzburg had been implanted with a customized skull plate. The transplant was specially made for the fracture and then successfully transplanted. Without this technology, the boy would probably have died.
Why has 3D bioprinting not yet become widespread?
Dr. Harald Unterweger: A bladder is a comparatively simple organ. In more complex body parts such as the kidney or heart, on the other hand, many cells interact with each other, which leads to greater complexity. Compared to a bladder, which is basically just like a shell, these organs cannot simply be printed like that. This is a complex 3D structure, which entails a number of difficulties. And to be clear from the outset, we are not currently in a position to print complex 3D-printed organs. That is indeed a vision of the future. But we are well on the way, as many steps have already been taken in this direction in recent years.
How does bioprinting work?
Dr. Harald Unterweger: The basic principle is similar to that of a classic 3D printer, where the filament is heated until it is liquid. The liquid plastic is then applied and printed layer by layer. It is similar with bioprinting. There are bioinks. These are applied spot by spot to a layer and then also applied layer by layer.
What is bio-ink?
Dr. Harald Unterweger: In principle, bio-ink is a mass that can be compared to toothpaste in terms of its viscosity. It mainly contains human cells. In order to print these cells successfully, growth factors and support structures must be used. If only the cells were printed, the result would look like a runny fried egg. However, by using support structures such as hydrogels or gelatine, complex layers can also be built up. The difficulty is actually not necessarily printing a three-dimensional structure. In 2019, for example, a group of researchers from Israel printed a miniature heart that actually looks like a cherry-sized human heart. It has no function, but the cells are inside. The big difficulty is to supply the cells with nutrients. In other words, creating microstructures that supply the cells with nutrients. This is the big challenge that still needs to be overcome before really complex large organs can be printed.
How are the various components brought together in bioprinting?
Dr. Harald Unterweger: In classic 3D printing, a support material is usually applied in layers. However, there is also the concept of using several nozzles to combine and print different materials. This also exists in bioprinting, where different nozzles are available and different cell types can be combined with each other, for example. A heart is not just made up of heart cells, but of different cells that interact with each other. However, just giving the cells a three-dimensional structure does not make an organ. It may look good and be easy to present, but it still has no function. To come back to the example from Israel with the miniature heart: This heart has no heartbeat. The cells are there, but the interaction between the cells is not.
What are the advantages of bioprinting?
Dr. Harald Unterweger: Bioprinting has many advantages. Basically, there is a very high demand for artificial organs. There are currently almost 8,500 people on the waiting list for a donor organ. At the top of the list are kidneys. Then come organs such as the heart, liver, pancreas and lungs. These are the five most frequently needed donations. However, there are only just under 1,000 donors per year. The demand is therefore immense and could be met by bioprinting. When a patient comes in and needs a new heart, they could go to the printer, load a model and print out the heart. It still has to mature a little, but the organ could be made available much faster than before.
In addition, printed mini-organs can already be used today to study how drugs work. When a new drug is currently being developed and its effect is to be observed, studies are usually first carried out on cell cultures. Petri dishes are used for this purpose, in which cells are arranged flat in 2D. The interactions with the individual cells are very low there. An active substance is then applied to the cells and it is observed whether the cells die, survive, express, etc. In a complex material such as our printed organs, the possibility of investigating interactions is much better. This means that there is a flow, i.e. a dynamic system. This does not exist in cell culture. There is only the Petri dish in which the cells sit and wait for something to happen. In a complex model, completely different phenomena and mechanisms can be investigated in the flow.
In addition, not only can organs be printed, but organs with a defect can also be specifically produced. For example, a cancerous organ can be used to investigate the effectiveness of drugs in certain diseases. These mechanisms are already being investigated today.
And in the medium term, it is also the case that animal experiments, which are necessary for medical development, can be further reduced. This is because bioprinting will make it easier to work with a "primary" material.
Which professions are primarily involved in bioprinting?
Dr. Harald Unterweger: A whole range of different professions are involved along the value chain. On the one hand, there are the biologists and biotechnologists who work on the inks and on the interaction of the various materials with the cells. Then there are the engineers who build the printers and develop new printing techniques. And finally, there are the researchers and doctors who use these materials and hopefully one day will be able to implant them in people.
In what year could bioprinting become a reality?
Dr. Harald Unterweger: That's a bit like guessing with a crystal ball. The fact is that a lot has happened in the last five to ten years. I wouldn't rule out the possibility that we could still see it happen. It's difficult to put an exact year on it. It may well be that we can generate one or two technical advances or that artificial intelligence will help us make a big leap. This could be the case in ten, twenty or even thirty years' time.
The interview was conducted by Dr. Tanja Jovanovic, Head of Innovation Management at Bayern Innovativ GmbH.
Bioprinting: Organs from the 3D printer?
Imagine a world where waiting for organ donations is a thing of the past. A world in which customized, life-saving organs simply come out of a 3D printer. Sounds like a dream of the future? Maybe not for much longer. Find out more about bioprinting from Dr. Tanja Jovanovic and Dr. Harald Unterweger in this episode.
