You can 3D print just about anything these days. I can order a mad-scientist action figure in my own likeness or print a specialized electric guitar. Novelties aside, this technology has practical and life saving applications with proven effectiveness in customized prosthetic limbs and medical implants (such as pacemakers). With this technology branching into the field of medicine, it seems just a matter of time until we are printing entire biological structures, but can we ever print fully functional organs?
Growing in vitro organs is the holy grail of medicine; the ability to generate a human organ outside of the body would revolutionize modern medicine. Progress is being made on this front, researchers were recently able to use stem cells to grow a human ear on the back of a rat1; remarkable as this research is, it still relies on an animal to grow the organ. With advancing technology, many are wondering if it will one day be possible to construct an organ outside of an animal’s body entirely.
Scientists tackled one aspect of this in a recent study. Laronda et al explored the possibility of 3-D printing a structural support for a synthetic ovary2. Using a special gelatin ink, these researchers were able to print scaffolds that could then be strategically populated with cells. The preciseness of this technique allowed not only for a proof-of-concept method for organ generation, but also created the opportunity to explore scaffold geometry required to make a functional ovary.
Constructing an organ scaffold is not just constrained by current technology; it is limited by our knowledge. Organs are not simply a mass of cells, they are complex structures and any old gelatin platform isn’t going to work. Organs need to protect the cells, and create structural support for them without interfering with their function. In the case of an ovary, cells need support to maintain their shape, but they also need to secrete hormones and release an egg during ovulation.
The authors experimented with the size and angle of the gelatin matrix to find a combination that balanced these needs. Their work resulted in a structure capable of hormone synthesis and the ability to ovulate in culture.
A biologically engineered ovary working outside of an animal is an amazing step forward, but taking it further, Laronda et al implanted the ovaries into surgically sterilized female mice. Remarkably, the implanted ovary became vascularized following the surgery, meaning the blood vessels connected to the bioengineered ovary and created circulation without further intervention from the scientists. The ovary integrated into the mouse’s body through natural regenerative processes, and eventually led to confirmed offspring. It seems that the human constructed ovary both integrated into the mouse body, and restored the ability to reproduce. It is hard to over state how amazing this research is, and how much excitement it has brought to the medical and scientific community.
We are a far distance away from printing a customized organ ready for transplant, but we are now quite a lot closer that we were just a few years ago.
- Bernstein, Jaime L., et al. “Fabrication of the First Full-Scale Human Auricular Chondrocyte Derived Ear Scaffold for Clinical Application.” Plastic and Reconstructive Surgery–Global Open 5.4S (2017): 94-95.
- Laronda, Monica M., et al. “A bioprosthetic ovary created using 3D printed microporous scaffolds restores ovarian function in sterilized mice.” Nature Communications 8 (2017).