Dual Dynamic\nCovalently Crosslinked Alginate Hydrogels\nwith Tunable Properties and Multiple Stimuli-Responsiveness

Abstract

Alginate is a biopolymer that can\nbe crosslinked with\ncalcium ions\nto fabricate cytocompatible hydrogels. However, using calcium ions\nto crosslink alginate provides limited properties and functions to\nalginate hydrogels, restricting their biomedical applications. Here,\nphenylboronic acid-functionalized polyethyleneimine (PBA-PEI) was\ndeveloped to introduce two orthogonal dynamic covalent crosslinks\nin the alginate hydrogels, where PBA-PEI was used to crosslink alginate\ndialdehyde (ADA) through imine bonds and boronate ester bonds. The\ngrafting degree of PBA in the PEI structure was applied to fine-tune\nthe properties of PBA-PEI/ADA hydrogels, including the rheological\nproperty, mechanical strength, swelling behavior, and antibacterial\nactivity. In particular, the highly sensitive boronate ester bonds\nin the network enabled PBA-PEI/ADA hydrogels to be responsive to several\nstimuli, such as glucose, fructose, and hydrogen peroxide. Taken together,\nPBA-PEI/ADA hydrogels with tunable properties and multiple stimuli-responsiveness\nhave been demonstrated as smart biomaterials for advanced biomedical\napplications.