This Process Builds Organs One Drop at a Time

Current methods use sodium alginate as the main agent for bioprinting. However, the sodium alginate doesn't work well with certain types of cells. The team used hydrogelation through an enzyme -- horseradish peroxidase -- which builds up cross-links between phenyl groups. The horseradish peroxidase adds polymer in the presence of hydrogen peroxide. It's also found in the root of horseradish. 

However, hydrogen peroxide can often damage cells. Thus, the researchers devised a way to limit the contact between hydrogen peroxide and the cells to make sure the cells stayed alive. With this method, more than 90 percen to the cells were viable. 

[see-also]

Lead author, Shinji Sakai said, "Printing any kind of tissue structure is a complex process. The bio-ink must have low enough viscosity to flow through the inkjet printer, but also needs to rapidly form a highly viscose gel-like structure when printed. Our new approach meets these requirements while avoiding sodium alginate. In fact, the polymer we used offers excellent potential for tailoring the scaffold material for specific purposes."

"Advances in induced pluripotent stem cell technologies have made it possible for us to induce stem cells to differentiate in many different ways," co-author Makoto Nakamura says. "Now we need new scaffolds so we can print and support these cells to move closer to achieving full 3D printing of functional tissues. Our new approach is highly versatile and should help all groups working to this goal."

While the study of printing organs themselves are still incredibly important to the ultimate goal of viable 3D printed organs, perfecting the ink could be a crucial step in that process. 

And the promises of bioprinting continue to be goals for biologist, engineers, and chemical engineers around the world. Lee Mun Ching, a biologist who specializes in pharmacology and physiology, told Open Bio Medical: 

"3D bioprinting hold several promises in the medical field. This technology could revolutionize the way we conduct basic research, drug testing, toxicology assays and many more. And while we are impatiently waiting for organ printing, it is never to early to ponder on the hurdles that we will inevitably have to address once it becomes a reality."

The findings of the Osaka University team can be found in the latest edition of Macromolecular Rapid Communications.