To the long list of household objects, jewelry, tools, clothes and knick-knacks that you can now 3D print, add ovaries.

A team of scientists from the Northwestern University Feinberg School of Medicine and McCormick School of Engineering created a bioprosthetic ovary that not only allowed a mouse to ovulate, but also give birth to healthy baby mice.

The man-made ovaries were actually a bit of serendipitous by-blow of the researchers' principal experiments designed to boost hormone production and restore fertility in mice.

"This research shows these bioprosthetic ovaries have long-term, durable function," said Teresa K. Woodruff, a reproductive scientist and director of the Women's Health Research Institute at Feinberg. "Using bioengineering, instead of transplanting from a cadaver, to create organ structures that function and restore the health of that tissue for that person, is the holy grail of bioengineering for regenerative medicine."

Unlike the 3D printed green plastic gimcracks that boutique shop in the mall makes, ovaries are printed from a gelatin-like substance made from broken-down collagen. The trick was in finding an organic material rigid enough to be handled during surgery and porous enough to naturally interact with the mouse's body tissues.

"Most hydrogels are very weak, since they're made up of mostly water, and will often collapse on themselves," said Ramille Shah, assistant professor of materials science and engineering at McCormick and of surgery at Feinberg. "But we found a gelatin temperature that allows it to be self-supporting, not collapse, and lead to building multiple layers. No one else has been able to print gelatin with such well-defined and self-supported geometry."

All fine and dandy for Mickey and Minnie, but what impact might this work have on humans? The researchers were testing the boundaries of lab-boosted mouse fertility to gain some insight into how to restore fertility and hormone production in women who have undergone adult cancer treatments or those who survived childhood cancer and now have increased risks of infertility and hormone-based developmental issues.

"What happens with some of our cancer patients is that their ovaries don't function at a high enough level and they need to use hormone replacement therapies in order to trigger puberty," said Monica Laronda, co-lead author of the research. "The purpose of this scaffold is to recapitulate how an ovary would function. We're thinking big picture, meaning every stage of the girl's life, so puberty through adulthood to a natural menopause."

The research has been published in Nature Communications.