In order to successfully 3D print the ovary, there were three requirements the scientists needed: oocytes ( immature egg cells), the hormone-releasing cells that support oocyte growth, and a flexible but strong structure that would be able to support the development of the cells into a functional organ. The base structure for the ovary was 3D printed from gelatin, which is found in Jell-O in its most famous form but is also made from animal skin. The team tested various configurations and sizes of the cell scaffold in order to determine the most viable design, which was formed by solid struts in a criss-cross pattern.
The multiple anchor points of the criss-cross scaffold made it a friendly environment for oocyte cells to latch on and grow healthily. Scientists introduced ovarian follicles to the scaffold, because each follicle contains the oocyte cell and the supporting cells within its round structure. After implantation, mice that had previously had their ovaries surgically removed restored their hormonal cycles, ovulated, gave birth to healthy mouse pups, and were even able to nurse their pups until it was time to wean them.
As many as 1.5 million women are infertile in the United States alone, according to the CDC. The scientists that developed the 3D printed ovary hope that its successful trial in mice is a promising development towards a practical human application, although the transition may be a long way off. Even the development of a hormonal cycle in mice with the implanted ovaries could be a huge benefit for human applications, since hormone imbalance can often be linked with infertility and the hormonal system is involved in so many measures of health in the body.
In order for the implant to work in humans, the 3D printing process will also need to incorporate stem cell technology. But scientists on the study believe that transitioning from skin cells to stem cells will be a relatively easy process thanks to 3D printing. Since the rigidity and structure of the artificial ovary proved so important in successful trials in mice, the Northwestern team believes that they will be able to customize a structure appropriate for humans with the same 3D printed approach.