Diels–Alder “click” chemistry for the cross-linking of furfuryl-gelatin-polyetheramine hydrogels

Abstract

This paper deals with the design of biopolymeric hydrogels after the chemical cross-linking of gelatin through the Diels–Alder (DA) reaction. Furan modified gelatin (Gel-FGE) was prepared by the reaction of furfuryl glycidyl ether with the free amino groups present in the gelatin. A Jeffamine®-based bismaleimide was employed as a cross-linking agent and the influence of the amount of cross-linker used on the final hydrogel properties was studied. The DA and retro-DA reactions were followed by ultraviolet spectroscopy and the final properties of the hydrogel assessed. Scanning Electron Microscopy was used to analyze the structure of the final material and rheology studies confirmed the formation of a chemically cross-linked network. The swelling behavior in response to external stimuli such as pH and salt concentration was also studied. By virtue of the DA “click” reaction, biopolymer-based cross-linked hydrogels, with promising properties for biomedical applications, were obtained in a simple one step procedure free of catalysts, additives or coupling agents.