UC Berkeley researchers have invented a 3D-printing process that can print biological matter and has the potential to make bioprinting tissue engineering more efficient, according to a study published in the American Society of Mechanical Engineers Digital Collection.
In creating this printing process, the researchers decided to use multilayer cryolithography, which allowed them to simultaneously print parallel 2D layers and freeze the layers together to form a 3D structure, according to the study.
“It’s like making a hamburger in a very cool — cryogenic — solution. You already print multiple layers, and you basically pick up one layer and stack them on top of each other,” said campus researcher Zichen Xiao, who worked on this project for his master’s degree capstone thesis. “You put the bottom bread there first and put whatever layer you want on top of it. By the process of freezing, it keeps its rigid structure, and the cells are still alive.”
According to Xiao, this process overcomes two major obstacles that are present in the field of bioprinting. The first is that material made for bioprinting is usually soft and thus, cannot sustain its own weight. The second significant challenge is that 3D printing takes a long time to execute — by the time a section is printed, the older cells on the bottom may have died.
Capstone project advisor Gideon Ukpai said the project itself faced some additional challenges.
“We had some challenges with trying to transport the layers and assembling them,” Ukpai said. “The layers binding together after the fact was also a challenge.”
To solve these issues, the final iteration of the experiment was carried out using two 3D printers, one robotic arm and other fixtures to ensure that the layers were printed onto the structure quickly and that the layers were frozen to bond them together.
Xiao said this innovation can be applied in a number of ways. The process can be used for tissue engineering or bioprinting. The study also found that only 10 percent of the world’s needed organ transplantation is currently being met. This new printing process could create a more efficient process to meet this need.
According to Xiao, another application could be in the food industry. The material the team used to print with was so viscous that the group had to create a new nozzle that could handle the pressure of the substance. Xiao said this technology could potentially create food that people with digestion and chewing issues can eat.
Both Xiao and Ukpai said they believe that this technology can still be improved. Ukpai plans to expand upon this research, and Xiao said he believes this technology may have limitations when it comes to mass manufacturing.