An unexpected role of an extra phenolic hydroxyl on the chemical reactivity and bioactivity of catechol or gallol modified hyaluronic acid hydrogels

Abstract

We present here a new insight into the chemical reactivity and bioactivity of dopamine (DA) and gallic acid (GA) and their hyaluronic acid (HA) conjugates. Our data suggest that HA-GA...

Sequential Cross-linking of Gallic Acid-Functionalized GelMA-Based Bioinks with Enhanced Printability for Extrusion-Based 3D Bioprinting

“…Catechol-functionalized polymers with metal ions have been proven to have rapid network formation, pH-tunable cross-linking, and self-healing activity. , The concentration of metal ions and pH can be used to precisely control the polymer network and their rheological properties . However, only a few studies have reported the application of GA–metal ion coordination chemistry to obtain printable biomaterial inks. ,− …”

“… 16 However, only a few studies have reported the application of GA–metal ion coordination chemistry to obtain printable biomaterial inks. 17 , 19 − 21 …”

Interpenetrating Gallol Functionalized Tissue Adhesive Hyaluronic Acid Hydrogel Polarizes Macrophages to an Immunosuppressive Phenotype

“…Both these approaches are inefficient, rendering a poor coupling yield. To circumvent this we modified the carboxylate residues of GA to a hydrazide derivative as they are known to undergo proficient EDC coupling owing to a lower pK a of hydrazides over amines [35] . To achieve this we first transformed the carboxylate groups of GA to methyl ester followed by nucleophilic displacement with aqueous hydrazine (80% solution) to obtain GA-hydrazide in quantitative yields.…”

“…The hydrazide derivative of GA was characterized by 1 H and 13 C NMR spectroscopy (Figure S2 and S3 in SI). We have recently shown that compared to hydrogels obtained by NaIO 4 oxidation of dopamine conjugated HA, the hydrogel obtained by GA functionalized HA displayed faster oxidation at physiological pH and possess higher tissue adhesive properties [35] . In this study, the GA functionalized HA was grafted with carbodihydrazide (CDH) groups as a biorthogonal moiety that facilitates covalent crosslinking reaction with aldehyde functionalized HA derivative.…”

“…This clearly suggests that the grafting of GA in HA gels promote the formation of secondary network that stabilizes the gel and prevent excessive swelling (Table S2). We believe this is attributed to the unique capability of the gallol moiety to undergo oxidation that generates radicals and undergo intermolecular dimerization [35] . Such secondary stabilization decreases the segmental mobility of the polymer chains and reduces the pore size, favoring a stiffer and stable matrix formation.…”