Are you an athlete with a crummy joint? Accident victim needing a new nose? In the future, making more cartilage for these body parts may be as simple as hitting "Control-P."
3D printing, long the hope of those needing a replacement kidney or liver, has now advanced into the field of cartilage regeneration, thanks to a team of Wake Forest University researchers led by Tao Xu. His group has developed a machine that combines two popular 3D printing techniques, electrospinning and inkjet work, to print viable cartilage, according to a paper published in the journal Biofabrication.
A bit of background: Inkjet printing, a technique much like conventional printing that involves depositing fine layers of material to create a 3D structure, has already been used to create skin, blood and bones. Meanwhile, electrospinning, or the use of a charge to draw very fine fibers from a liquid, is another 3D printing technique, used largely to print synthetic materials.
When we can machine-produce skin and bone, why is cartilage, of all body types of tissue, so difficult to print? Cartilage is a funny substance; in ears, noses and joint sockets, it needs to combine extreme flexibility with basic structural integrity. Mike Senese of Wired magazine explains why neither inkjet nor electrospinning alone could previously make cartilaginous tissues.
Electrospun materials typically don’t have the ability to promote cellular growth, nor do they have the flexibility needed for cartilage replacement. And inkjet printed materials lack the structure and strength needed to support the loads that cartilage carries.
The solution? Make a machine that allows both inkjet printing and electrospinning, printing one layer of electrospun synthetic fiber for every layer of inkjet-printed cartilage cells, according to the paper. Though some of the tissue constructs experienced “layer separation” directly after printing, most of what the research team printed grew into -- you guessed it -- a cartilage structure in vitro.
Of course, more research is needed before the scientists at Wake Forest can start printing out new noses. For one, their new electrospinning-and-inkjetting machine hasn’t made very big pieces of cartilage yet -- the research group’s sample was only one millimeter thick. For another, the cartilage they used to create their sample was taken from rabbit ears -- not human cartilage, which is what’s used in current cartilage replacement. Much more work is needed before these tiny “tissue constructs” become the kind of printed cartilage that can go into human bodies.
Still, here’s to those who worked on the project and who have allowed us to witness great advances in this field in recent years. It may just make all our osteoarthritic futures a little brighter.