Electrically Modulated Semi-Convertible Hydrogel Microneedles for Programmable Insulin Delivery.

Insulin delivery systems that mimic pancreatic secretion offer promising improvements in type 1 diabetes management. However, current systems struggle with sustained and precise release. Inspired by the dynamic secretion mechanisms of the pancreas, a wearable electrically modulated semi-convertible hydrogel microneedle system for insulin delivery has been developed for long-term self-regulation in the treatment of type 1 diabetes. This system combines a non-covalent electro-responsive silk fibroin network and a polyethylene glycol/chitosan matrix, integrated with flexible electrodes that exhibit a partial gel-sol phase transition under 1.2 V electrical stimulation. In hyperglycemic conditions, the electric field induces silk fibroin phase transition, triggering insulin release through electrostatic interactions and polymer network expansion. Once blood glucose normalizes, insulin is released passively via diffusion when the electric field is turned off. In type 1 diabetic mice, a single microneedle patch provides segmented control, with a 10-min stimulation effect lasting up to 8 h, extendable to 16 h with further stimulation. This system offers a versatile, sustained, and precise drug delivery strategy with significant potential for chronic disease management.