Effect of Ionic Functional Groups on the Oxidation State and Interfacial Binding Property of Catechol-Based Adhesive

Abstract

Adhesive hydrogels were prepared by copolymerizing dopamine methacrylamide with either acrylic acid (AAc) or N-(3-aminopropyl)methacrylamide hydrochloride (APMH). The effect of incorporating the anionic and cationic side chains on the oxidation state of catechol was characterized using the FOX assay to track the production of hydrogen peroxide byproduct generated during the autoxidation of catechol, and the interfacial binding property of the adhesive was determined by performing Johnson-Kendall-Roberts contact mechanics tests tested over a wide range of pH values (pH 3.0-9.0). The ionic species contributed to interfacial binding to surfaces with the opposite charge with measured work of adhesion values that were comparable to or in some cases higher than those of catechol. Addition of AAc minimized the oxidation of catechol even at a pH of 8.5 and correspondingly preserved the elevated adhesive property of catechol to both quartz and amine-functionalized surfaces. However, AAc lost its buffering capacity at pH 9.0, and catechol was oxidized at this pH. On the other hand, catechol formed a cohesive covalent bond with the network-bound amine side chain of APMH at basic pH, which interfered with the interfacial binding capability of APMH and the catechol.

Sequence-defined positioning of amine and amide residues to control catechol driven wet adhesion

“…With the sequence-controlled oligomers we could additionally show the effect of catechol/amine spacing. In case where the catechol and amine residues are in close vicinity (11), the adhesion energy is drastically amplied compared to the oligomers with an additional EDS spacer between catechol and amine (6 and 9). In addition, the adhesion was affected by changing the position of the catechol and amine residues (6 and 9).…”

“…Such synergy between catechol (DOPA) and charged groups could be conrmed using synthetic polymers combining anionic and cationic residues. [11][12][13] Inspired by the adhesive properties of the Mfps, a wide range of polymers with high DOPA content were synthesized toward advanced adhesives and surface coatings. 1,6,[14][15][16][17][18][19][20][21][22][23] However, sequence effects like the spacing of the charged groups and catechol residues were given little attention for the design of such mussel-inspired synthetic adhesives.…”

Mussel-Inspired Catechol-Functionalized Hydrogels and Their Medical Applications

“…The incorporation of cationic functional group to catechol groups containing adhesion elevate the interfacial binding to various inorganic substrate [101,102,103]. Narkar et al [104] have made a systematic study about the effect of ionic side chain on oxidation state and interfacial binding property of catechol-functionalized hydrogel. They prepared adhesive hydrogels by copolymerizing dopamine methacrylamide (DMA) with either acrylic acid (AAc) or N -(3-aminopropyl)methacrylamide hydrochloride (APMH).…”

Toward improved wound dressings: effects of polydopamine-decorated poly(lactic-co-glycolic acid) electrospinning incorporating basic fibroblast growth factor and ponericin G1

“…Dopamine has strong adhesive abilities because of its catechol functional group and the terminal amino functional group of lysine. 47 Dopamine is capable of self-polymerization in an alkaline solution, forming a highly viscous PDA layer on the surface of the material. 48 Many studies have shown that PDA coating can greatly improve the hydrophilicity and biocompatibility of biomaterials.…”