At best, doctors and surgeons were content with transplants from donors where possible. However, these are always lacking and pose a risk of rejection by the patient’s body. If we could print 3D new custom body parts to suit the individual, it would solve many problems. A new ear implant first introduced by 3DBio Therapeutics has achieved just that.
Developed to order
Smallness is a condition in which the structures of the outer 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 concept of the “new ear”. It is designed to treat a condition known as microtia, in which the structure of the outer ear is underdeveloped on one or both sides. Each year, about 1,500 babies are born with the disease in the United States. Current treatments include taking a sample of cartilage from the patient’s sides and manually engraving it to resemble a typical ear shape. This can then be implanted with a low chance of rejection, as it is made from the patient’s own cells. Alternatively, the implants can be made of synthetic materials and placed under the skin. The AuriNovo ear follows the biological path, but eliminates the need to collect a large amount of cartilage from the sides. In contrast, in the pioneering surgery, only half a gram of cartilage was taken as a biopsy from the existing structure of the patient’s ear. From there, special cells called chondrocytes were isolated. These cells, which are used to form cartilage, were then cultured in a proprietary nutrient solution to multiply into their billions. Diagram describing the method used to create and implant AudiNovo. Credit: 3DBio Therapuetics From there, the chondrocytes grown from the patient’s sample were combined with a collagen-based “biomelanin”. The resulting mixture was then used in a special 3D printer built specifically to create biological structures. The ink and printer are specially designed to keep everything sterile to reduce the chance of complications or rejection from the patient’s body. The printer made a copy of the patient’s fully developed ear from the biological material, albeit inverted to fit the opposite side of the head. The ear was then given a special biodegradable housing for support and shipped via cold storage. Shortly after arrival, the printed structure was implanted under the patient’s skin, which stretched around and took the expected shape of a fully developed human ear. The casing is intended to be absorbed by the body over time, leaving behind the printed cartilage structure. It is still early and the clinical trial involving 11 patients is still ongoing. However, the prospects for the technique are good. The resulting structure is made of biocompatible materials as well as cells grown by the patient himself, making rejection unlikely. In addition, as the implant is made of living material, it should remain flexible and maintain the appearance and feel of a normal human ear in the long run. Basically, the structures of the outer ear are relatively simple things. They are largely scaffolding, although they play a role in receiving the sound that comes to the ear. They also have the advantage that they are largely made from a simple material, without any complicated biochemistry, veins or nerves. Thus, ear reconstruction is perhaps a perfect starting point for creating new body parts from scratch. The lessons learned from this work could help scientists working on more complex problems with greater mechanical complexity. This could lead to the creation of new mating surfaces for the joints or better rehabilitation treatments for people with injuries. Long-term goals include 3D printing of entire organs, such as the kidneys and liver. However, there is a lot of work to be done before we can recreate functional instruments, with all the inputs and outputs of liquids and their complex chemical processing capabilities. Overall, the AudiNovo is a steady first step into a new future, where custom body parts can be printed on demand. We hope that the clinical trial will provide excellent results for all patients involved and that it heralds further progress in the field. Ear frame images: 3D Bio Therapeutics
