Design, Characterization, and Biocompatibility of Modular Biopolymer-Based Single- and Double-Cross-Linked Networks Hydrogels

The synthesis of the modular ketone-rich dextrin acetoacetate (DXTAA) and its application in the click chemistry-based synthesis of single-cross-linked network (SN) and double-cross-linked network (DN) biopolymeric hydrogels are reported. DXTAA is obtained in a base-catalyzed transesterification reaction between dextrin and tert-butyl acetoacetate. DXTAA forms covalently cross-linked SN hydrogels with a hydrazide derivative of alginate (Alg-SDH) via hydrazone linkages in aqueous solution without any initiator, heat, or catalyst. The presence of carboxylate groups in Alg-SDH enables the preparation of DN hydrogels using calcium ions as an ionic cross-linker. The swelling ratio and the stability of the hydrogels are shown to be pH-dependent; the DN hydrogel exhibits considerably higher stability at pH 7.4 compared to the SN hydrogel. Both hydrogels are shown to be noncytotoxic and biocompatible. Thus, DXTAA can be considered a promising cross-linker for the in situ click synthesis of biocompatible gel.