An international team of researchers from universities in China, Belgium and the U.S. has made a bioprinting breakthrough by successfully 3D printing an ear inside the body of a mouse. The study, entitled “Noninvasive in vivo 3D bioprinting,” details the team’s innovative method for printing an ear in vivo without any surgical intervention.
The method employed by the researchers uses near-infrared light to polymerize a tissue-like bioink in vivo without the need for any invasive surgical incisions. Typically, if bioprinting were used to repair defective tissue in vivo, it would rely on the use of ultraviolet light to polymerize material, a process which would require surgery to expose the tissue to the the light. By using near-infrared light, however, the team has found a less invasive solution.
According to the researchers, the process begins with the injection of a bioink into the patient (in this case a test mouse). The bioink is made up of a combination of hydrogel particles and cartilage cells, which are both biocompatible. Once the ink has been injected, a near-infrared light source is directed at a digital micromirror device chip, which emits the light into a pre-determined pattern that is subsequently projected onto the patient. The light is capable of penetrating the skin to react with the bioink inside the body, causing the material to harden into a specific shape.
In the test case, the printed in vivo ear structure started to take shape within seconds under the mouse’s skin. The final ear took about a month to grow, because the cartilage cells had to cultivate and mature. At this stage, the researchers are continuing their work and conducting more tests, but they are all optimistic that the technique will be viable for repairing human ears that suffer damage from sporting injuries or accidents.
The collaborative research team has members from the Sichuan University in China, the University of California San Diego and Ghent University. The full study can be found in the journal Sciences Advances.