Covalent Binding of Maleic Anhydride Copolymer Monolayers to Polyacrylamide Hydrogels

• Published in: Macromolecular chemistry and physics Vol. 219; no. 17
• Main Authors: Müller, Christina, Ansorge, Michael, Espig, Martin, Zschoche, Stefan, Schiller, Jürgen, Pompe, Tilo
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.09.2018
• Subjects: Amides; Anhydrides; Binding; Biomimetics; Cell adhesion; Cell adhesion & migration; Copolymers; Coupling; Hydrogels; Hydrogen bonding; Joint ventures; Maleic anhydride; Monolayers; NMR; Organic chemistry; polyacrylamide; Substrates; surface functionalization
• ISSN: 1022-1352; 1521-3935
• DOI: 10.1002/macp.201800206

Physicochemical surface modifications of soft hydrogel layers are beneficial tools for modulating biomimetic substrate properties in cell adhesion studies. Recently, a layered system of a polyacrylamide hydrogel with a monolayer coating of maleic anhydride copolymers was introduced, however, without a detailed study of the chemical coupling mechanism. Herein it is shown that a stable coupling results from covalent binding of maleic anhydride residues to the primary amides of polyacrylamide via imide bond formation. The many anhydride moieties of the copolymer chains allow for coupling with a low‐yield reaction at mild conditions. Furthermore, hydrogen bonding and polar interactions are excluded to account for a stable binding of maleic anhydride copolymers to polyacrylamide hydrogels. Covalent bindingof maleic anhydride copolymers to polyacrylamide hydrogels are shown to be enabled by imide formation under mild reaction conditions. Thereby the coupling mechanism of these functional hydrogel interfaces is revealed which were previously applied in various cell adhesion studies.