Growing organs a few ink drops at a time

December 27, 2017, Osaka University
Photograph of a 3D hydrogel construct obtained through drop-on-drop multi-material bioprinting. Credit: Osaka University

Printed replacement human body parts might seem like science fiction, but this technology is rapidly becoming a reality with the potential to greatly contribute to regenerative medicine. Before any real applications, "bioprinting" still faces many technical challenges. Processing the bio-ink and making it stick to itself and hold the desired printed gel structure have been proving particularly difficult especially in inkjet printing. Few methods currently exist for gluing bio-ink droplets together and these do not work for every kind of cell, motivating new alternative approaches.

Building on their previous work, researchers at Osaka University have now refined an enzyme-driven to sticking biological ink droplets together, enabling complex biological structures to be printed. They recently published their findings in Macromolecular Rapid Communications.

Lead author, Shinji Sakai says, "Printing any kind of tissue 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."

Currently, sodium alginate is the main gelling agent used for inkjet bioprinting, but has some compatibility problems with certain cell types. The researchers' new approach is based on hydrogelation mediated by an enzyme, horseradish peroxidase, which can create cross-links between phenyl groups of an added polymer in the presence of the oxidant .

Although hydrogen peroxide itself can also damage , the researchers carefully tuned the delivery of cells and hydrogen peroxide in separate droplets to limit their contact and keep the cells alive. More than 90% of the cells were viable in biological test gels prepared in this way. A number of complex test structures could also be grown from different types of cells.

"Advances in induced 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 3-D printing of functional tissues. Our new approach is highly versatile and should help all groups working to this goal."

Explore further: New method developed to 3-D print fully functional electronic circuits

More information: Shinji Sakai et al. Drop-On-Drop Multimaterial 3-D Bioprinting Realized by Peroxidase-Mediated Cross-Linking, Macromolecular Rapid Communications (2017). DOI: 10.1002/marc.201700534

Related Stories

Bioprinting has promising future

November 15, 2012

Writing in the journal Science, Professor Derby of The School of Materials, looks at how the concept of using printer technology to build structures in which to grow cells, is helping to regenerate tissue.

Success in the 3-D bioprinting of cartilage

April 28, 2017

A team of researchers at Sahlgrenska Academy has managed to generate cartilage tissue by printing stem cells using a 3-D-bioprinter. The fact that the stem cells survived being printed in this manner is a success in itself. ...

Recommended for you

Uber filed paperwork for IPO: report

December 8, 2018

Ride-share company Uber quietly filed paperwork this week for its initial public offering, the Wall Street Journal reported late Friday.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.