3D-printed ovaries just enabled this mouse to give birth

A lab mouse has given birth to a new litter of pups, which in and of itself wouldn't be notable. The big deal here is how the mouse gave birth, or more specifically put, the physical alteration that made the seemingly impossible, well, possible: 3D-printed ovaries. This isn't the first time we've seen 3D-printing technology used for biological applications — there are those 3D-printed eye cells, for example. This is, however, a milestone as far as reproduction-centric printing goes.

The study was recently detailed in the journal Nature, where researchers detail a process that involves creating ovaries by printing gelatin made from collagen in layers called scaffolds. The study describes this thusly: "A gelatin ink was developed to create a well-defined microporous, bioactive scaffold with extrusion-based 3D printing." The researchers explain that they used the gelatin due its its collagen origins, something that is found extensively in mouse (and human) ovaries.

The researchers then go on to detail the complex process of printing various types of scaffolds and the ultimate process that produced the ideal instances of follicle survival — something that is 'dependent on pore geometry,' according to the researchers. A total of three scaffold designs were created via printing, each with different layer angles (30, 60 and 90, to be precise).

A series of tests ultimately found 'that the 30° and 60° scaffold architectures support hormone production, oocyte maturation and ovulation,' according to the study, with the 60-degree scaffold winning out. A small ovary was then cultivated from the bioprinted mass and was implanted in the place of a normal ovary in a mouse via surgery. After three weeks, researchers observed that blood vessels had formed for the ovary in a way similar to the natural organ.

Researchers refer to this as a 'bioprosthetic ovary,' and the mice containing them were eventually allowed to mate with male mice. Three of the recipients then went on to successfully give birth to litters containing one or two pups. Hormone production in the mice appeared normal and they were able to feed their pups via lactation. The success is a milestone step toward potentially creating such bioprosthetic organs for humans to restore fertility.