The fabrication of a novel type of positively charged acid-disintegrable microgel loaded with insulin by electrostatic interactions and covalently immobilized with glucose oxidase (GOx) and catalase by inverse emulsion polymerization is reported, aiming for glucose-regulated insulin release by utilizing GOx/catalase cascade enzymatic reactions to trigger local pH decrease and acid-cleavage of crosslinking moieties. At the same time, a local pH decrease within the microgels also leads to the diminishment of net surface negative charges of encapsulated insulin. The above two factors both synergistically contribute to the prominently enhanced insulin release at high glucose levels (∼10-20 mM) compared to that in the absence of glucose.
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