The rise of 3D printing has facilitated some impressive feats in the medical world, helping to create everything from a new upper jaw for a cancer patient to a titanium sternum and rib cage. Now, a team from Northwestern University in Chicago has used the technology to produce a prosthetic ovary, which was successfully implanted into mice, allowing them to bear live young.

To create the pioneering prosthesis, the researchers used a 3D printer to create a scaffold from the animal protein collagen. The team had to ensure that the structure was strong enough to be handled during surgery, as well as spacious enough to house the hormone-producing cells and immature eggs – known as oocytes. After some trial and error, a crisscrossing strutted structure was decided upon, as it provided the necessary rigidity and size, while providing multiple points at which cells could anchor.

Once the collagen scaffold was printed, the team seeded it with ovarian follicles to create the finished bioprosthesis. At that point, the researchers turned towards testing the product, implanting their creation into mice whose ovaries had previously been removed.

The results of the experiment were extremely positive, with the mice ovulating, and eventually giving birth to healthy young, which they subsequently nursed as normal. The bioprosthesis was able to support the growth of blood vessels without any external stimulation, and the implant was found to have restored the animals' hormone cycles. It's believed that similar effects might be achieved with human patients.

Furthermore, the researchers believe that the bioprosthesis could be of particular use for treating survivors of childhood cancers. An estimated 1 in 250 adults has survived a childhood cancer, the treatments for which cause an increased risk of infertility as adults.

Clinical trials would have to take place before patients could benefit from the pioneering new treatment, but in the long run, it could have a big impact on the field.

"We developed this implant with downstream human applications in mind, as it is made through a scalable 3D printing method, using a material already used in humans," said lead study author Monica M Laronda, PhD. "We hope to one day restore fertility and hormone function in women who suffer from the side effects of cancer treatments or who were born with reduced ovarian function."

The findings of the research were presented at the Endocrine Society's annual meeting in Boston.