Doctors Invent New Way to 3D Print Inside the Body


Researchers from Harvard Medical School and Duke University claim to have created a novel method for 3D printing within the human body by using ultrasonic waves to irradiate an injectable biocompatible ink.

The team's study expands on a previously created photo-sensitive ink that hardens when exposed to light beams, as described in a new publication published in the journal Science. This allows scientists to assemble complex biomedical structures gradually.

However, a statement regarding the research states that light can only reach a few millimeters into the tissue of a particular patient. Sound waves, however, can go much farther.

The novel procedure known as "deep-penetrating acoustic volumetric printing" (DVAP) has the potential to advance the idea further by enabling scientists to replace broken heart valves or even repair bones with no invasive open surgery.

"DVAP relies on the sono-thermal effect, which occurs when sound waves are absorbed and increase the temperature to harden our ink," said coauthor and Duke biomedical engineering associate professor Junjie Yao in the statement.

"Ultrasound waves can penetrate over 100 times deeper than light while still spatially confined, so we can reach tissues, bones and organs with high spatial precision that haven’t been reachable with light-based printing methods," Yao added.

The biocompatible "sono-ink" can form complicated structures by hardening it in place after it reaches the desired location using a specialized ultrasonic probe.

"The ink itself is a viscous liquid, so it can be injected into a targeted area fairly easily, and as you move the ultrasound printing probe around, the materials in the ink will link together and harden," said Y. Shrike Zhang, coauthor and associate bioengineer at Harvard's Brigham and Women’s Hospital, in the statement.

"Once it’s done, you can remove any remaining ink that isn’t solidified via a syringe," Zhang stated.

The best part is that the scientists could create new forms of their "sono-ink," such as more flexible and pliable heart valves and sturdy scaffolds that resembled bones.

The researchers created a unique structure to seal off a portion of a goat's heart and prevent blood from collecting inside the organ in a series of three tests. With no issues, the tissue toughened and securely attached to the tissue. The group also took care of a chicken leg's internal bone problem.

The researchers also showed how a unique hydrogel for sono-ink may release a chemotherapeutic medication into a liver gradually.

However, as usual, much more research is needed before we can be positive that the same technology would function in humans.

"We’re still far from bringing this tool into the clinic, but these tests reaffirmed the potential of this technology," said Zhang in the statement. "We’re very excited to see where it can go from here."


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