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Skip to 0 minutes and 7 seconds Microtia is a congenital condition. And it can vary incredibly from person to person. So it is, in its essence, an abnormality of development of the ear, particularly the outer ear. But it can affect the middle ear as well. And there’s two aspects of it. One is it has a cosmetic problem. And the other thing is a functional problem, which is hearing loss. The hearing loss aspect is easier to treat now with implantable hearing aids. But the cosmetic problem, or even to regenerate, recreate an outer ear on which a person can hang a hearing aid if they wanted to, that’s a very difficult problem.

Skip to 0 minutes and 49 seconds And at the moment, plastic surgeons spend a lot of time trying to carve up what looks like a natural ear. But they try and get graft most reliably from the rib cage, which has quite a bit of morbidity, as you understand. And the trouble is that even in the best of hands, the complication includes of scarring and failure of the graft. So for a child– so typically, these operations are being done on a 10-year-old. You can imagine that that’s fairly– there’s a range of morbidity. How do you think 3D printing could help in what you’re confronted with on a daily basis? Yeah, and I mean, that’s exactly the benefit of it. Firstly, the cosmetic match.

Skip to 1 minute and 32 seconds So you can get data from one side and match it to the data from the other side. You can control it. And most importantly, then there’s not that donor site morbidity. So you’re not having to open up a child’s rib cage and get grafts from there. So I can see the 3D printing could play a number of roles in what you do on a daily basis. Yeah. I mean, there’s use for it now, and there’s use for it in the future. And some of the examples of use for it now, use it in pre-operative planning, use it in communication with our patients. And of course, used in the future is bioprinting.

Skip to 2 minutes and 13 seconds And I think, as you know, the face is very three-dimensionally complex. And it’s unique in every person. TO use 3D printing to regenerate the operative field we’re operating on, like, say, of the ear or their jaw and plan the operation beforehand, if we’re reconstructing, we can have a more precise reconstruction. So when we get into the patient in the operating theatre, we are saving time, and we’re getting a better result. Right. And is it useful also in communicating with the patient about what you’re doing? Oh, absolutely. Yeah. I mean, we have– as a hearing imbalance specialist, most of my patients can’t hear. So they rely on visual cues a lot.

Skip to 2 minutes and 52 seconds And so rather than me relying on my diagrams of complex anatomy, which they have never seen– most of us have not seen the inside of an ear– for me to just show them on a model, they understand it instantly. And it really helps me inform them, empower them. And then they’re better patients because they’re more motivated and they feel more in control of what’s happening to their bodies. So that’s the immediate impact that 3D printing’s having in your day-to-day activities. For replicating the ear, it’s really quite complex, isn’t it? I mean, the distribution of mechanical properties across the ear. Exactly. I mean, as you know, we’ve been breaking it apart. And different parts of the ear has different mechanical properties.

Skip to 3 minutes and 35 seconds And then to be able to replicate that, make the scaffold strong enough but soft enough to make it keep that three-dimensional shape. In the challenge of the molecular forces that the tissue interacts with, that’s the biggest challenge. It seems like a very simple concept, but it is actually really, really complex to achieve. Yeah. And so once we understand that distribution of mechanical properties across the ear. Of course, it’s possible use finite element modelling just to predict what that 3D structure should be as it’s printed for the ear to give the exact replication of shape, but also mechanical properties. And that’s very unique to 3D printing, to be able to do that. Exactly right. Exactly right.

Skip to 4 minutes and 23 seconds And then it’s even more challenging when you do multiple materials. Yes. Yeah, so that brings me to the multiple material bit. So now we’ve got one single material with different internal structures to give us the shape and to give us the distribution of mechanical properties. And now we need to simultaneously print a more gel-like material. And would that gel-like material actually contain the patient’s cells? Yeah. Well, the idea is the gel-like material is a support. But then you can put the patient’s cells on top of that for it to grow, for it to differentiate.

Skip to 5 minutes and 1 second And as you know, we’re sort of trying to work towards getting some of the patient’s host cells, host differentiated cartilage cells, and then using some of their stem cells, which we can get from fat or blood or bone marrow, and put them in together. So using that gel-like material– which is the bioink, I suppose– with stem cells, they’re nourished, and they differentiate like you want them to rather than differentiate into scar tissue. And who knows? Down the track we might find that the molecular constraints of those cells or the molecular demands of those cells may then make us go back and redesign or readjust the scaffolds according to their demands. So yeah, it is very complex.

Skip to 5 minutes and 49 seconds And is there a need to encourage the growth of a vascular structure within that 3D-printed ear? Of course, yes. As you know, all living tissue relies on blood supply. And that’s the basic principle of any reconstructive work. So the more any tissue can draw blood vessels in, the more advantage it has, the more likely it’s going to thrive. We have a number of challenges here with a 3D-printed ear. We need to have those structural materials that will give us the replication of the shape and the distribution of mechanical properties, printed along alongside a gel material containing the patient’s cells that can differentiate in the appropriate cartilage. And then finally, with this vascularisation challenge.

Skip to 6 minutes and 35 seconds And I’d imagine that those two components will be important. But it might also be important to distribute other bioactive components to encourage that vascularisation. Yeah, exactly. And I mean, it may be that we have to have more bioactives towards the source of the blood supply or the pedicle, which we sort of invite the blood vessels. [INAUDIBLE] vascular genesis, per se. There are a fair few steps here that we need to plan for. And it’s all in the design of that, which we can control using the 3D printing.

The problem

Associate Professor Payal Mukherjee is working with our researchers to develop 3D bioprinted solutions for patients with Microtia.

The need

Previously we’ve introduced the need to 3D print materials that provide structural support, yet have some flexibility, so that they are compatible with biological systems. Researchers are currently working towards ear implants for cosmetic purposes and in the future, more complex vascular structures which have the ability to process sounds to the brain.

The rapid emergence and convergence of advances in material science, fabrication machinery, and cell biology in the last 5 years is helping us solve major clinical challenges such as the need for a reconstructed ear, enabled by 3D bioprinting.

Your turn

Think about yourself, your family, friends and the people you know. Use the discussion space to identify a clinical challenge that you or somebody you know has experienced, and imagine how 3D bioprinting may be used in the future to aid or remedy this clinical challenge.

Please note

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This video is from the free online course:

Bioprinting: 3D Printing Body Parts

University of Wollongong