Synthetic bone grafts—made of calcium phosphate ceramics, or from bone harvested from patients or cadavers—are nothing new. But that's just the most simple vision of what artificial bone can be. Working at the intersection of art, technology, and design, artist Amy Karle is also in the midst of her own boundary-pushing bone grafting project.
For Regenerative Reliquary, she is hacking bone cells to 3D-print intricately designed hand-bone replacements. Karle calls her project a fusion of generative art and regenerative medicine, the idea being that the two disciplines don't have to be so philosophically and practically distinct.
Karle chose the hand design because, she says, it is a unique human feature. She's using human cells to study what happens when these forms are taken out of the environment in which they are usually grown. Karle also hopes to discover if the bone cells will create unique and unexpected patterns as they go. (It’s also possible they won’t grow at all.)
The process involves training stem cells to become bone. "Essentially, this means that if it were to be applied medically, a patient’s own stem cells could be used, and—if all works well—turn to bone," says Karle, "which could be implanted into the body without rejection, since it would be of their own genetic material."
Karle is undertaking Regenerative Reliquary as part of an artist residency at Autodesk’s Pier 9 program in San Francisco. Tucked away inside Pier 9’s creative workshops is a Bio/Nano/Programmable Matter group, which is investigating the design spaces enabled by biotechnology and nanotechnology. Karle collaborated closely with this group and many others at Autodesk, including the Fusion 360, Within Medical, and Ember teams.
With the help of Autodesk Bio/Nano’s Chris Venter and Ember’s John Vericella and Brian Adzima, Karle 3D-printed the design on the microscopic level using a Ember 3D printer extruding PEGDA hydrogel, a "biofriendly blank slate" ideal for cell growth that disintegrates over time.
After sterilizing and preparing the 3D prints for cell growth, Karle seeded them with stem cells and allowed them to grow. These stem cells—called mesenchymal stem cells (MSCs)—can differentiate into a variety of cell types. Karle and the team are hoping for bone growth, but they can't be sure of what will happen. The cells are being fed a steady supply of nutrients and gasses, as would normally occur in the human body. It will take about two years for the cells to grow into Karle's design.
"This specific hand form I designed is not intended to go back into the body," Karle says. "However, it does bring up very interesting applications for health care, cosmetic enhancements, and transhumanism, as well as questions about what it means to grow a new form outside of the body from the material of the body and the possibilities of what could be made out of human cells."
Since she and her collaborators cannot yet achieve blood vessels, tendons, ligaments, and skin all in the same form, Karle is only working with the spongy part of bone. Her design could incorporate the skeleton and potentially hold the bones together in a new way.
What would the utility be in creating geometric or other intricately printed designs? Karle believes that scientists and doctors could design new forms to grow in cells and tissues for medical reasons. But she also thinks that "cosmeceutical" companies, plastic surgeons, and entrepreneurs could potentially create new designs to augment the human body. For some people, having a new skeletal form, for the hands or other bones, could be attractive because it hadn’t existed before. For others, they may design complex bones that are never intended to go into the body at all.
"There are many people who want to improve on the body that they are given, for many reasons," Karle says. "Personally, I was contemplating what I would add. I actually have a space for a bone—my skull never fused. However, I’m not interested in filling that. I’ve been thinking if I was going to create an implant for my body, it would be enhancing my clavicles, working with what I already have and then building on it to make a slightly exaggerated version."
Karle is confident that if her workflow were to be medically refined, its main benefit would be a lower risk of complications when people receive bone grafts or implants. Imperfect fits could become a thing of the past, reducing operation time and money for patients. And because the grafts are made of the patient’s own genetic material, a 3D print might well reduce the probability of rejection. Making such technology open-source would also allow people to come up with the best design work flow, instead of centralizing the technology in the hands of big companies.
"The benefit of making this as art is that I can test some of these theories and technologies, develop materials and processes and experiment outside of the scope of protocols that would have to be followed if this was to be developed as an implant," Karle says. "This is true generative art to me. Making this as art allows me to study and develop these ideas, find out if I can get this to work, and see what we can learn and what issues arise in the process, both technically and conceptually."
"I hope this project serves as a catalyst to explore issues this work raises about the awe and mystery of life, synthetic biology, the future of medicine and implants, accentuating or modifying our bodies and who we want to make ourselves into, and contemplating things we could make from the building blocks of life," Karle says.
"My ultimate hope would be to inspire researchers, hospitals, [and] biomedical, pharmaceutical, and cosmeceutical companies to take these ideas and continue exploring this kind of work, providing a work flow that is easy to access and follow as a departure point for their own research.
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[All Images: courtesy Amy Karle/Autodesk, 2016]