BY Noah W. | 3DP4E
In the United States, 78,837 patients are waiting on organ donations, but only 3,407 have been made this year (at time of publication). Now, imagine that line shortening or disappearing all together. Thanks to 3D Printing, we're not that far off from that becoming a reality.
In the late 1990's the scientists at the Wake Forest Institute for Regenerative Medicine 3D printed the synthetic building blocks needed to grow human bladders, and thrust bio-printing into the limelight. Shortly after, in the early 2000s, Clemson University bioengineer Thomas Boland started modifying ink-jet printers to dispense biological ink and make 3D objects. Organovo, one of the first bio-printing companies was founded in 2007, and is currently printing liver tissue samples for drug testing and research, and is hoping to develop a functional liver in the near future.
While a lot more complicated, the processes for printing organ material and typical filament are pretty similar. Both types of printers have cartridges and nozzles that print ink layer by layer on a platform. The challenges in bio-printing lie in the differences.
While we know what organs look like, they still have to be personalized for each person that would need one, which involves scanning the patient using CT or MRIs. Doctors than use the scans to create a blueprint for the organ. Instead of plastics or metals, bio-printers use the cells of the organ they're printing along with binding agents. Printers may also use stem cells, bioengineered materials, and other human compatible substitutes, such as in the case of a 3D-printed titanium jaw implanted into an 83-year-old woman or the 2013 case of a man with a 3D printed plastic skull. After printing, the organ needs to be incubated so it can properly fuse and work like a real organ. That part is the real sticking point keeping organ-printers out of hospitals for now.
According to Anthony Atala (who led the Wake Forest team that created those famous lab-grown bladders), the problem lies in finding materials that can be used to print body parts, and then getting them to develop outside the body, Also, once printed, the procedure is more complicated than shoving the new organ into a patient. Organs are complicated, and just because the organ exists doesn't mean it will work. In the words of Cornell engineer Hod Lipson:
– Hod Lipson
"You can put the cells of a heart tissue in the right place together, but where's the start button? The magic happens after printing has taken place."
Lipson also notes that there's still no software powerful enough to make organ models that researchers can consult before printing.
Aside from making 3D-printed organs work, scientists also find it hard to create blood vessels. Organs need arteries, veins and capillaries but these shapes are hard to print. This May, a team from Brigham and Women's Hospital used the sugar-based molecule agarose as blood vessel templates. Fraunhofer researchers have also been developing their own technique since 2011, and Harvard scientist Jennifer Lewis is looking into printing organs with tiny spaces for blood and nutrient flow.
We've already seen success in organ printing. A team from the University of Louisville, successfully printed heart valves and small veins in April, with hopes of making a heart using a patient's cells in the future. Cornell bioengineers created a working ear out of living cells and injectable gels. Organovo has created a working mini human liver, however it can only survive for 40 days.
Roughly 90 percent of the patients in the organ waiting list need kidneys, and to meet demand, a group of Chinese scientists developed small, working printed kidneys, which can survive for four months. Atala too is looking for ways to 3D print a kidney, and even showed off a non-working model during his TED talk.
During that same presentation, he gave us a look at the future of 3D printed organic technology. He predicts a future where flatbed scanners could look at and assess a patient's wounds and then print directly on the patient's body.
Before we get there, there is still a lot of testing to be done in labs and med schools, followed by perfect specimens that can be transplanted into the bodies of waiting patients soon after.
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