Microneedle Patch Prepared from a Hydrogel by a Mild Method for Insulin Delivery

Most reported microneedle patches still suffer from a complicated preparation process and insufficient loading capacity for the glucose-responsive delivery system. Herein, based on the reversibility of the boronate ester bond, a novel gel was formed by mixing phenylboronic acid grafted sodium hyaluronate and polyvinyl alcohol. The insulin-loaded microneedle patch could be directly obtained by simply blending high-dose insulin and gel into the mold. The introduction of cellulose nanofiber was also found to be in favor of mechanical strength. The glucose responsibility could be achieved when the boronate ester bond was broken by glucose, leading to the change of crosslinking density and further controlling insulin release. In the hypoglycemic experiment of diabetic rats, the microneedle patches could effectively puncture the skin and maintain normal blood glucose levels for an extended period. The facile preparation process and high loading capacity give this microneedle patch a great chance in mass production.