The quest to develop viable, transplantable 3D printed body parts continues, with major victories coming here and there as scientists successfully implant organs like thyroids and ovaries into mice. But while accomplishments like those make the headlines, there are far more times when scientists 3D print a body part in a lab only to have it turn out to be structurally unfit for transplantation or unable to survive as part of a living thing.
One area of focus has been 3D printing body parts made of cartilage, such as the ear. While 3D printed ears have been created using cartilage taken from elsewhere in a patient’s body, the goal is to 3D print an entirely new ear from stem cells, without the need to remove cartilage from anywhere else within the patient. A group of researchers from SRM University and SIMS Hospital in India are making their own progress toward 3D printed ears, an area where they have dedicated almost two years of work. Earlier this week, the scientists revealed an ear that they had 3D printed, and stated that the technology was used to 3D print pieces of cartilage that continued to survive and grow when implanted in rabbits.
The researchers have not published or patented their process, but they did share details at a press conference about what they call an experiment in progress. As they described it, the cartilage cells, or chondrocytes, were taken from a piece of ear cartilage removed from a rabbit. The cells were then grown in a solution, composed of natural and synthetic substances to provide the cells with nutrition, for nearly three weeks. Once the cells expanded, they were seeded onto a biodegradable, biocompatible scaffold that was 3D printed in the form of an ear. When enough cells had grown – 107 per square centimeter to be exact – the cells were implanted in a rabbit.
“We still have a long way to go before we give this to a child with a birth defect, but we now have a definite path,” said SIMS Hospital Medical Director Dr. K Sridhar, a senior plastic surgeon. “We will be doing a large scale animal study to reconfirm our results before we start any human trial.”
“We kept it under the skin in the rabbit’s abdomen for three months. We also left an empty scaffold on the other side of the abdomen,” said Dr. Shantanu Patil, head of the translation medicine department at SRM University.
“A large part of the scaffold had disappeared,” said Dr. Patil. “If we had left it for a little longer we would have had better results. We are now using this sample to check on the tensile strength and other mechanical properties.”
According to pathologists from the laboratory, there was nothing largely abnormal about the samples taken from the scaffold. The researchers will now proceed further in their work; they have been given permission by the Committee for the Purpose of Control and Supervision of Experiments on Animals (CPCSEA) to expand the experiment to 18 more rabbits.
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