Microneedle-array patch with pH-sensitive formulation for glucose-responsive insulin delivery

Glucose-responsive insulin delivery systems show great promise to improve therapeutic outcomes and quality of life for people with diabetes. Herein, a new microneedle-array patch containing pH-sensitive insulin-loaded nanoparticles (NPs) (SNP(I)) together with glucose oxidase (GOx)- and catalase (CAT)-loaded pH-insensitive NPs (iSNP(G+C)) is constructed for transcutaneous glucose-responsive insulin delivery. SNP(I) are prepared via double emulsion from a pH-sensitive amphiphilic block copolymer, and undergo rapid dissociation to promote insulin release at a mild acidic environment induced by GOx in iSNP(G+C) under hyperglycemic conditions. CAT in iSNP(G+C) can further consume excess H2O2 generated during GOx oxidation, and thus reduce the risk of inflammation toward the normal skin. The in vivo study on type 1 diabetic mice demonstrates that the platform can effectively regulate blood glucose levels within normal ranges for a prolonged period.