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 recent publication published in the journal Science. This allows scientists to gradually assemble complex biological structures.
However, a statement regarding the research states that light can only reach a few millimeters into the tissue of a particular patient. On the other hand, sound waves may go far farther.
With the new method known as “deep-penetrating acoustic volumetric printing” (DVAP), scientists may be able to restore broken bones or even faulty heart valves without resorting to invasive open surgery.
“DVAP uses the sono-thermal effect, which happens when sound waves are absorbed and raise the temperature to solidify our ink,” coauthor Junjie Yao, an associate professor of biomedical engineering at Duke University, said in a statement.
“Ultrasound waves can penetrate more than 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 said.
The biocompatible “sono-ink” may be used to form complicated structures by hardening it in place after it reaches the desired location using a specialized ultrasonic probe.
Y. Shrike Zhang, coauthor and associate bioengineer at Harvard’s Brigham and Women’s Hospital, stated in the statement that “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.”
“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 were able to 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. Without any issues, the tissue toughened and securely attached to the tissue. The group also took care of a chicken leg’s internal bone problem.
Additionally, the researchers showed how a unique hydrogel for sono-ink may release a chemotherapeutic medication into a liver gradually.
However, as usual, much more study is needed before we can say with certainty if the same technology may be used to humans.
“We’re still far from bringing this tool into the clinic, but these tests reaffirmed the potential of this technology,” Zhang stated in the announcement. “We’re very excited to see where it can go from here.”