When it comes to repairing human bodies, there is one big difficulty: it is difficult to find spare parts. It is simply not possible to buy a knee joint or a new lung off the shelf.
At best, doctors and surgeons have contented themselves with transplants from donors where possible. However, they are always in short supply and are at risk of rejection by the patient’s body.
If we could 3D print new custom parts / body parts to suit the individual, this would solve many problems. A new ear implant created by 3DBio Therapeutics has achieved just that.
Grown to order
Microtia is a condition in which the external structures of the ear are underdeveloped, on one or both sides. Credit: Klaus D. Peter, CC-BY-SA-3.0
The implant is known as AuriNovo, so named to evoke the meaning of “new ear”. It is used to treat a condition known as microtia, in which the structure of the outer ear is underdeveloped on one or both sides. About 1,500 babies with the disease are born in the United States each year.
Ongoing treatments include taking a sample of cartilage from the patient’s ribs and hand-carving to resemble a typical ear shape. It can then be implanted with a low probability of rejection, as it is made by the patient’s own cells. Alternatively, implants can be made of synthetic materials and placed under the skin.
The AuriNovo ear follows the biological path, but denies the need to collect large amounts of cartilage from the ribs. Instead, in pioneering surgery, only half a gram of cartilage was taken as a biopsy from the patient’s existing ear structure. From there, special cells called chondrocytes are released. These cells, which are used to form cartilage, are then cultured in a patented nutrient solution to multiply in their billions.
Diagram outlining the method used to create and implant AudiNovo. Credit: 3DBio Therapuetics
From there, the chondrocytes grown from the patient’s sample are combined with a “bio ink” based on collagen. The resulting mixture is then used in a special 3D printer specifically designed to create biological structures. Both the ink and the printer are designed specifically to keep everything sterile to reduce the likelihood of complications or rejection by the patient’s body. The printer created a replica of the patient’s fully developed ear from the biological material, albeit inverted, to match the opposite side of the head.
The ear was then given a special biodegradable maintenance shell and sent by refrigerated storage. Shortly after arrival, the imprinted structure is implanted under the patient’s skin, which stretches around and assumes the expected shape of a fully developed human ear. The shell is designed to be absorbed by the body over time, leaving behind the imprinted cartilage structure.
It is still early days, and the clinical trial involving 11 patients is still ongoing. However, the prospects for technology are good. The resulting structure is made of biocompatible materials, as well as cells grown by the patient himself, which makes rejection unlikely. In addition, because the implant is made of living material, it must remain flexible and maintain the appearance and feel of the ordinary human ear in the long run.
In essence, the outer ear structures are relatively simple things. They are largely skeletons, although they play a role in helping to capture sound coming into the ear. They also have the advantage that they are made largely of a simple material, without complicated biochemistry, veins or nerves.
Thus, ear reconstruction is perhaps the perfect starting point for creating new body parts from scratch. The lessons learned in this project could help scientists working on more complex problems with greater mechanical complexity. This can lead to the creation of new matching surfaces for the joints or better restorative treatments for those with injuries. Long-term goals include 3D printing of entire organs, such as the kidneys and liver. However, there is still much work to be done before we can recreate functional organs with all their fluid inlets and outlets and complex chemical processing capabilities.
Overall, AudiNovo is a solid first step towards a new future, where custom body parts can be printed on request. We hope that the clinical trial will lead to great results for all patients involved and that it portends further progress in this area.
Ear Frame Images: 3D Bio Therapeutics
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