Adipic acid dihydrazide is commonly used as a functional group to allow for HA cross-linking to polymers containing aldehyde groups or that are aldehyde-functionalized, like HA-aldehyde or PEG-aldehyde. These biomaterials are attractive for their tunable properties and low cytotoxicity.

Degree of functionalization (50-80%)

Hyaluronic acid (HA) is a ubiquitous extracellular matrix component, which makes it attractive for use in medical applications for it′s biocompatibility and low immunogenicity. HA-based polymers are used to make hydrogels for a wide variety of applications from tissue engineering and regeneration to drug delivery and bioinks for 3D bioprinting. To make hydrogels, HA has to be derivatized with groups that can cross-link to to other functionalized polymers.