LAUSR

We report the multifunctionality of a small adhesive functional group called gallol (three hydroxyls attached to benzene), which is the ubiquitous moiety found in many vegetables and fruits. First, the chemical tethering of gallols to a polysaccharide backbone and the addition of another gallol-rich compound, oligo-epigallocatechin gallate, result in the spontaneous gelation of the hyaluronic acid-gallol, and the cross-linking is due to the extensive level of hydrogen bond formations from both gallol-to-gallol and gallol-to-hyaluronic acid. Second, we found that the gallol-involved cross-linking is reversible, resulting in a shear-thinning effect of the hyaluronic acid-gallol hydrogels, allowing this hydrogel system to be injectable. Third, due to gallol’s superior ability to bind proteins via noncovalent interactions, the hyaluronic acid-gallol hydrogels exhibit spontaneous loading of proteins from a buffer solution to the hydrogel inside against the concentration gradient (i.e., active entrapment phenom...