Scheme 1. Schematic Illustration of the Reactions between PEGDM and Gelatin Microgel or Tissue Substrates.

Catechol groups are oxidized to form reactive quinone, which can result in cohesive cross-linking and curing of the adhesive (A), and interfacial cross-linking with nucleophilic functional groups (i.e., −NH₂, −SH) found on either the gelatin microgels (B) or tissue surface (C).