Hyaluronic acid-based hydrogels show promise as bio-ink in the 3D printing of tissues

Regenerative medical materials, such as bio-inks, can be used in bio-engineering procedures like the 3D printing of tissues.

Madison Godesky and David Shreiber studied thiol-modified hyaluronic acid (HA-S) and polyethylene glycol diacrylate (PEGDA) for their effectiveness as scaffolds in regenerative medicine, on which tissue can be grown.

“We recognized the potential of the HA-S and PEGDA materials ideal for tuning the stiffness and bioactivity,” said Shreiber. “We were investigating the material for a different application in tissue engineering when we recognized that the way the chemistry worked for hydrogel formation and maturation could be ideal for independent control of the properties.”

The authors found two crosslinking reactions in the HAS-PEGDA hydrogel system that occur in timescales: a rapid, Michael-type nucleophilic addition reaction between HA-thiols and PEG-acrylates, and a slower maturation of disulfide crosslinks from remaining thiols. These reactions can be used to independently tune the mechanical properties of the gel.

“For HA to be used as a scaffold it must be crosslinked to have mechanical strength and integrity. It should also have ligands for the cell to attach,” said Shreiber. To accomplished this, the authors introduced acrylated peptide-ligands to promote cell adhesion and validate that bioactivity could be introduced into the hydrogels.

They hope to further this work by culturing cells inside of a gel in three dimensions instead of two dimensions. They are currently working toward this by including short peptide sequences that can be broken down by enzymes produced by the cells encapsulated in the gels.

Source: “Hyaluronic acid-based hydrogels with independently tunable mechanical and bioactive signaling features,” by Madison D. Godesky and David I. Shreiber, Biointerphases (2020). The article can be accessed at https://doi.org/10.1063/1.5126493 .